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1. c 0s secsecssoveseceecccrcnvsescecccctccssssserccuccesssssecseucsevssecsesescuensees 28 nl e ERE M 29 Swilches ccu cele cane RIED a MUNDUS COSI S OD IDEET EC IEEE 30 www allitebooks com INSERERE DER m GeceeteanSech wean a AEE 31 Bridges arid ROUTERS 2 epe teet etr ebrei eios tee A e aKa NENE pre Muret eunt tre deus 32 Combination Boxes sisis repr pb nep pr C bb et pee Reese ace ge edic e du eS ea antes 33 A HOW COMPUTER NETWORKS ARE ORGANIZED 35 TCP ZIP Networks uetus center erro N ER DR ERER RR Te ER ER EU Een RUN SEE ga EU ere ei p Eres 36 Naimes and Addresses i arcos eta eaae ets uses che sen ehe eee desea 36 NEM 41 a EUER 41 ifconfig mt B OA 43 PING E E T AS 43 Une E 44 5 DESIGNING YOUR NETWORK 47 Identifying Current and Future Nodes ssssses eee 48 Wrxe gofecgccm ER 50 Hame RUM WARING m 51 Trunks and Branches Using Secondary Switches 53 What AboUt WII 2 05 2 cgasesaceacaseascessecscriedcs sadsdenrapancadacbaedesndebaneaenaaapnedeenabenectdeaondes 54 6 INSTALLING THE NETWORK CONTROL CENTER AND ETHERNET CABLES 55 Connectors Wall Plates and Surface Boxes es e 55 Ethernet Cale m 56 Pushing Cable Through Walls sess 57 The Control Center 58 AG POWER ERU L 61 Modems Routers and Switches sseseeseee eene 62 Adding a DSL or
2. x cw aw Figure 12 1 Use the Folder Options window to turn Simple File Sharing on or off In the Advanced Settings box scroll down to the bottom 5 To turn Simple File Sharing on or off click the Use simple file sharing Recommended checkbox The file sharing function is active when you see a checkmark in the checkbox 6 Click OK to save your setting and close the Folder Options window In spite of its name Simple File Sharing offers five access levels which you might consider more complicated than simple However each of the five levels is useful in certain situations Level 1 My Documents Files are only accessible to the file private owner Level 2 My Documents Files are accessible to the file owner default and administrators Level 3 Locally shared Other users on this computer have documents read only access the file owner and administrators have full access Level 4 Read only shared Local and network users have read documents only access the file owner and admini strators have full access Level 5 Read and write All users have full read and write access WARNING f you want to restrict access to any of your files be sure to protect your Windows user account with a password Level 1 The owner of Level 1 files and folders is the only person who can read them All the files in a Level 1 folder are also private Level 1 files and folders are only possible within your user profile the My
3. HUBS SWITCHES AND ROUTERS nodes it must have some way to connect any pair of nodes Large networks can have very complicated structures with many branches and extensions but the core of every network can be reduced to just a few patterns The simplified layout of a network is known as its topology The most common network topologies are a big loop known as a ring a hub system with everything connected to a central core called a star a common path not a loop that connects nodes using a time sharing method and a mesh in which there s a direct connection from every node to every other node Figure 3 1 shows simplified diagrams of each network topology In a loop network such as IBM s old token ring design data moves around the loop until it reaches its destination In the much more common hub system each data packet travels to a central location where a control device reads the address and sends it back out to the right destination Ethernet networks which include most small LANs are hub systems 28 Desktop computer computer Desktop computer Desktop computer NP ptop computer computer IN di Desktop computer Desktop computer Figure 3 1 Every network uses a specific topology Mesh topology is not common in small home or office networks but the wide area networks that connect your small network to the Internet often use mesh designs This chapter describes the equip
4. 5 Turn on your equipment in this order modem first router next and then the computer Leave the game console turned off for the moment 6 Confirm that the computer can detect the LAN and the Internet just as it did before you added the game console 7 Turn on the Xbox 360 console and make sure there is not a disc in the disc tray The Xbox Dashboard will display the Xbox Live area 8 Assuming you have already configured things like time and language the Gamer Profile screen will appear If you already have an Xbox Live membership in another location select Migrate your Xbox LIVE account If you re setting up a new account select Join Xbox LIVE 9 Follow the onscreen instructions to supply your contact information and gamer profile and to create or transfer an account Connecting Home Appliances to Your Network Chapter 15 They re not widely used today nor in many people s opinions useful enough to justify the added cost but home appliances with Internet connections are available and more will probably come along in the next few years Networked connections can allow you to control your household TV refrigerator micro wave oven and other appliances through the Internet or from a mobile telephone even when you re away from home Combined with built in diagnostic modules a network connection will also make it possible to identify problems and notify a service bureau that can either send back a software fix or dispat
5. Data Networks and What You Can Do with Them Chapter 1 The alternative to sneakernet is a network consisting of physical links that connect two or more computers and related equipment These links can use wires radio signals or a combination of both to move computer data and any other information that can be converted to and from computer data between any pair of network nodes Every computer connected to a network sends and receives data through a connector or radio antenna Depending on the data transfer speed and the network s specific requirements the computer might use a parallel port a serial port an Ethernet port a USB or FireWire port or a Wi Fi antenna Because these connectors and antennas move data in both directions they are input output ports or I O ports but that term is more often used to describe the computer s serial and parallel data connectors After you connect your computers together you will discover that you can do many things through the network that you may not have expected By the time you have lived with the network for a few weeks you won t think much about it but you ll use it all the time File Sharing When you connect your computer to a network you can allow other people to read and write files that are located on your computer s hard drives and other storage media and you can open and store files from other computers File sharing is one of the most common and the most convenient uses
6. Read amp execute A user with permissions to Read amp execute can view the contents of a file and run a program file but can t make changes or delete the file Read A user with Read permissions can view the contents of a data file but can t make any changes or delete the file Write A user with Write permissions can make changes but can t delete the file Special permissions Special permissions are administrative controls that most users don t need Click the Advanced button to set these options 7 Obviously some of these permissions overlap so if for example you allow full control you will also allow permission to modify read and write to the file To save your choices and close the Properties dialog click OK Printer Sharing The Network and Sharing Center also controls printer sharing Chapter 14 explains how to use this feature Password Protected Sharing Password protection assigns one more level of security to shared files When password protected sharing is turned on you can t open or edit files without a user account and password on that computer Media Sharing Media sharing in Windows Vista transmits music still pictures or videos through your network to a digital media receiver DMR such as a game console or a compatible home theater receiver Chapter 15 explains how to use media sharing File Sharing on a Macintosh Starting with OS X 10 2 the Macintosh operating system supports Windows file
7. c a M B LJ o Q Appearance Desktop amp Dock Expos amp International Security Spotlight Screen Saver Spaces Hardware Q Lal A Bluetooth CDs amp DVDs Displays Energy Keyboard amp Print amp Fax Sound Saver Mouse Internet amp Network A Mac QuickTime Sharing System gm b oO u u o Q LIES a b Accounts Date amp Time Parental Software Speech Startup Disk Time Machine Universal Controls Update Access Other NetUpdate Figure 11 10 Use the System Preferences window to set up your network connection Click the Network icon in the Internet amp Network group The Network window shown in Figure 11 11 will appear with detailed information about your network connection If your network has a DHCP server providing IP addresses the settings will automatically appear in the Network window Location Automatic Hd Built in Ethernet Connected Status Connected Built in Ethernet is currently active and has Bluetooth Q the IP address 192 168 1 103 Not Connected Built in FireWire gt re al 8 x Connected 2 Configure Using DHCP e Ama A IP Address 192 168 1 103 n T Subnet Mask 255 255 255 0 Router 192 168 1 1 DNS Server 64 255 237 242 64 255 237 243 Search Domains domain actdsitmp amp Click the lock to make changes Assist me C Revert Apply Figure 11 11 The Network window shows the current network conn
8. 1 Turn on both TVs and go to the destination player s Now Playing List The other DVR will appear at the bottom of the list of available programs Highlight the name of the distant DVR and press Select That DVR s Now Playing List will appear Choose the name of the show you want to transfer to this DVR and press Select The Getting Program screen will appear To watch the show while you re transferring it select Start playing on the Getting Program screen When the transfer is complete the name of the show will appear in this DVR s Now Playing List Other Things You Can Connect to Your Network 217 218 Chapter 15 Playing Video on a Computer Several of the same programs that play music on a computer can also handle video files Windows Media Player RealPlayer and QuickTime include both audio and video decoders Others such as VideoLAN hitp www videolan org and MPlayer are optimized for video Like other networked files you can use a player program on a client computer to view a video file from a server In most cases one or more video player programs automatically take control of specific file types so almost all video files will automatically load into an appropriate player when you select a file from an onscreen directory or file folder Connecting a TV to Your Network In rooms where you have a television set but no computer it s often possible to use a game console or other adapter to view movies and other di
9. 10 0 0 0 to 10 255 255 255 169 254 0 0 to 169 254 255 255 172 16 0 0 to 172 31 255 255 192 168 0 0 to 192 168 255 255 Fixed and Dynamic Address Assignments DHCP The computers and other nodes in your LAN can obtain their numeric IP addresses in one of two ways The person who sets up the network connection can assign a permanent address or a router or other network control device can automatically assign an address every time the device connects to the network A permanent assignment is called a fixed or static IP address an automatic assignment is a dynamic address How Computer Networks Are Organized 37 38 NOTE Chapter 4 Another LAN 103 75 201 47 Desktop computer 192 168 0 101 WAN 103 75 201 0 LAN side 192 168 0 1 WAN side 103 75 201 48 Another LAN 103 75 201 50 Printer 192 168 0 105 Figure 4 1 A router presents separate IP addresses to each network The method for assigning dynamic IP addresses is called Dynamic Host Configuration Protocol DHCP so the device that makes the assignments is a DHCP server In a LAN the DHCP server uses numbers from the reserved range on the Internet the servers use numbers from a range provided to your ISP by IANA Both fixed and dynamic IP address assignments can work equally well but all the devices on the network must use the same system otherwise more than one device might use the same number at the same time If your LAN incl
10. 174 184 175 178 181 types of 16 78 79 Wireless Network Connection programs 87 87 89 88 wireless settings 86 pigtails 85 printer servers 194 Wi Fi Alliance 79 Wi Fi Protected Access WPA encryption 54 78 90 91 136 160 174 176 179 181 182 183 194 217 Wii 220 221 WiMAX networks 174 Windows backup files 100 103 101 103 104 Backup or Restore Wizard 101 101 102 computer connections 22 computer to network connections 117 118 118 124 119 120 121 122 123 INDEX 265 Windows continued configuring for VPN 165 172 166 172 file servers 94 96 96 file sharing in Vista 131 136 143 137 142 file sharing in XP 131 132 132 136 134 135 firewalls 154 159 155 158 Home Server 95 96 96 208 215 infrared ports 21 IP addresses 111 111 112 Live Messenger 234 285 237 Media Audio 210 Media Center 208 Media Player 208 211 218 network adapters 73 74 Network Problem Solver 245 247 247 248 network profiles 118 Network Setup Wizard 118 122 119 120 121 network to Internet connections 111 111 112 772 115 OpenVPN for 173 Remote Desktop 226 remote desktop programs 226 229 227 228 servers 163 164 215 TCP IP 35 36 123 123 126 158 text commands for 43 44 troubleshooting info 247 updates and patches 185 188 186 187 Vista Home Premium 226 VPN servers for 162 165 165 Wi Fi control programs 87 87 88 88 Windows to Mac remote access 226 wired eq
11. DSL or video and several data outlets along with your modem router and switch 60 Chapter 6 AC Power Your modem router and switches will all need some kind of electric power If you re using a plywood panel as your control center attach an AC power strip with enough outlets for all your devices and at least one spare to the side of the panel closest to the nearest AC outlet near the bottom The control panel should be close enough to an outlet that the cable attached to the power strip can reach it without an extension cord In order to protect your equipment from damage caused by lightning strikes or other power surges use a power strip with a built in surge protector Many network devices use plug in transformers or power converters sometimes called wall warts that are bigger than a simple AC power plug so you will want a power strip that provides extra space between outlets like the one shown in Figure 6 4 This particular model also includes surge protection for a DSL telephone line Photo courtesy of APC Figure 6 4 This power strip is designed for oversize plug in power supplies As an alternative to a power strip consider using an uninterruptible power supply UPS that will provide backup power from a battery when your AC power fails A UPS is not a replacement for a generator but it will keep your network alive during short power disruptions Network control devices don t use as much power as a compu
12. purpose internal computer processor For example as Figure 2 12 shows a printer server could be a computer with a printer attached to it or a printer with an internal or external network adapter connected directly to the network Printer server Printer Printer server Printer Figure 2 12 A printer server can be either a computer with a printer connected to it or a dedicated printer server In a small network it s not unusual for the same computer to double as a client and a server For example in a home network the family s printer might be located in the kitchen where Mom has a computer on which she keeps the family s financial records and looks up recipes on the Internet The kitchen computer is the network s printer server When others in the house want to print something they instruct their own computer to send it to the printer through the network to the computer in the kitchen The computers operating systems know how to handle such print requests without interrupting other programs running on the printer server Clients and servers are important because they are essential network building blocks A client and server structure is often the very best way to add services to a network because it s an efficient way to share expensive hardware and software and it makes those services equally accessible to everybody For more details about adding and using servers see Chapter 9 Types of Network Connections 25
13. s private files The exception is a system administrator account that provides access and control to almost all files Passwords Passwords are the first line of defense against unwanted access to a com puter or a network If a would be intruder can t get the computer to start the operating system opening data files or using the network is a lot more difficult but not impossible a determined intruder with enough time and resources can often get around a password to open and read unencrypted files You may be tempted to set up your computer without a startup password but that completely defeats most of the computer s security features and those of the network connected to it Unless you re absolutely certain that no strangers will ever get close enough to turn on your computer or gain access through a wired or wireless network and you trust everybody else in the house or office to respect your privacy it s worth the extra time needed to enter a password every time you turn on the computer or connect to it through a network An effective password should be difficult to guess and long enough to make it hard to find with a brute force program a program that applies massive computing resources to trying one password after another until it stumbles upon the right one Too many people use one of these items as a password e Your own first name or middle name e The name of your spouse child or pet e Your mother s maiden n
14. ssssssssseee eee 89 WEE SOUT Ry oett e eM ede aeree ne e ve ba susie vals eee PESE de AADA 89 9 FILE SERVERS 93 Choosing a Computer to Use as a File Server 94 Windows Mac Linux or isses eee here ee eere e eene a i 94 Using a Serverfor File Storage 5 e rtr rer ee nr OP tre HEROS 96 Using Network Attached Storage een emnes 97 USB Device Servers ssssssseessssee eene m nm eeenen enne 99 Apple s AirPort Extreme oerte lect recette tete teet tested aiu 99 Backing Up Files to Server ix eodein tp erc Rr to dece PEL RR E een 100 The Windows Backup Program sese 101 Macintosh Backup Programs ssssee eee 103 Linux sand Unix Backups scissione an cest eter e rite etes 104 Using a Serysr at Home e Cera reete tre arte Ceci e pel tee 105 10 CONNECTING YOUR NETWORK TO THE INTERNET 107 The Internet From the Cloud to You sss 108 The MOdem 3 5 rette reset e odere eue cree ens dee ge Pres rre and 108 The Gateway ROUET n dcr ioter D Pe EE EE SERO UR RR ER ERR Hn 109 Individual Computers eo crier ta eoe eee fe ere te to tn ee tegunt pes 110 Configuring the Network Gateway see eem eene 115 NIU d 115 11 CONNECTING YOUR COMPUTER TO A NETWORK 117 Connecting Your Windows Computer to a Network sss 118 Creating a New Network Profile sss 118 Changing Your Computer s Network Settings 122 Connecting Your Maci
15. t work unless you use a numeric IP address to identify a destination DNS servers perform what seems like a simple task but this task is more complicated than it first appears because millions of domain names are out there and new ones are added all the time Every DNS server in the world has to keep up with all the adds moves changes and deletions It accomplishes this through a system of root servers that are continuously www allitebooks com updated If a local DNS server doesn t recognize a name it consults the root server that keeps up with that name s top level domain NOTE There s actually a hierarchy of DNS servers so a root server might end up consulting yet another server and so on up the line if it can t handle a name request itself When you set up your computer for access to the Internet you must specify the DNS servers that the computer will use to convert domain names to numeric IP addresses In most cases your Internet service provider or network manager will give you the numeric address of one or more nearby DNS servers If your primary DNS server is not accessible your computer will look for an alternate server if you have provided an alternate address It s generally best to use the DNS server address supplied by your ISP because the server with this address is probably closer to your own computer than any other server and the system works best when total demand for DNS service is spread among as many se
16. File and Printer Sharing for Microsoft Networks must be active for you to share access to a printer Click OK to save your settings and close the Properties window Instructing the Computer Acting as a Printer Server to Share the Printer Follow these steps to share a printer From the Control Panel select Printers and Faxes in Windows XP or Printers in Windows Vista A window that contains links to all of the printers and virtual printers connected to this computer will open Right click the printer you want to share with the network A pop up menu will appear 3 Select Sharing from the pop up menu The Properties dialog for that printer will open with the Sharing tab visible as shown in Figure 14 4 2 x amp Samsung ML 1740 Series Properties General Sharing Ports Advanced Color Management Security Printer About 1 9 You can share this printer with other users on your network To SS enable sharing for this printer click Share this printer Windows Firewall ts already configured to allow the shanng of printers with other computers on the network C Do not share this printer gt Share this printer Share name Don s Printer r Drivers If this printer is shared with users running different versions of Windows you may want to install additional drivers so that the users do not have to find the print driver when they connect to the shared printer Additional Drivers Figu
17. It s particularly important to label the wall outlets in a network without a control center Years from now when other people try to use your network after you ve moved away they ll need to know where the cable connected to each data outlet goes You can also use a small Ethernet switch to use more than one network device in the same room For example if there s a data outlet in a teenager s bedroom you could connect a four port switch to the wall outlet and connect a computer a game controller and an Internet radio to the household network through that switch ETHERNET NETWORK INTERFACES Every computer on a network uses some kind of internal or external connector to send and receive data to and from other com puters This connector along with the hardware that controls it is called a network adapter or network interface because it s the point of contact between the computer and the network In a small home or business network the network interface can be either an Ethernet port that communicates with the network through a cable or a wireless transmitter and receiver that exchanges radio signals with a Wi Fi base station This chapter describes the most common wired Ethernet network interfaces Chapter 8 provides similar information about connecting your computer to a network through a wireless interface 70 Built into the Motherboard Chapter 7 Every modern wired Ethernet interface has an eight pin socket
18. SSIDs and passwords for your Wi Fi network e The telephone numbers and other contact information for your ISP and the telephone company or cable service that supplies your physical Internet connection e Instruction manuals for each modem router access point or other net work device e A list of your network s users including names telephone numbers and logins e A diagram that shows how each computer and other device connects to the network e Passwords for each network server e Account names and passwords for your email service e A list of rooms that have wall mounted network outlets and the label on the other end of each cable e A log of adds moves changes and deletions to your network e A log of repairs including e The date and time each problem appeared e Adescription of each problem e What you did to fix the problem e The time and date of each call to a technical support center e The name and telephone number of each technical support person you talk to e The trouble ticket number or case number assigned to the problem by each support center WARNING Your network notebook might contain confidential information such as passwords and information about user accounts Therefore you should to keep it in a secure location such as a locked cabinet or drawer Viruses and Other Nasties If you can t find an obvious solution to a network problem it never hurts to run a complete scan for viruses worms Trojan ho
19. Settings Network Connections a Internet e Internet Explorer LY Mele E mail jf This Computer Mozilla Thunderbi Microsoft Word E Plata Control Panel Set Program fA FuliShot99 access and Defa ec America Online Connect To A Sound Fi x Dial up Connection Sk i Internet via MSN a A dacity Printers and Faxes Show all connections t E Notepad Ee 4 Search AllPrograms Run E Log Off Turn Off Computer Figure 11 1 Select the Show all connections option to open the Network Connections window From the Network Connections window select Network Setup Wizard The wizard s Welcome screen will appear From the Welcome screen click Next The Wizard will remind you to install and turn on all the computers and other components in your network Click Next again The wizard will look for a network connection and ask what kind of connection you re making as shown in Figure 11 2 INetwork Setup Wizard Select a connection method Figure 11 2 Select the Other option to add this computer to your LAN Select Other and click Next The Wizard will ask for more details as shown in Figure 11 3 Network Setup Wizard Other Internet connection methods Figure 11 3 Select the This computer connects to the Internet directly or through a network hub option to connect to your LAN Connecting Your Computer to a Network 119 120 NOTE Chapter 11 Select the Th
20. The Number of DHCP Users setting defines the highest number in the address range in this case 192 168 1 149 In some systems the server asks for a range of numbers instead of the starting number and the number of users In either case allow for more DHCP users than the number of machines currently connected to the network so the server can continue to support your network after you add more devices Subnet Masks The subnet mask setting specifies which part of the IP address changes for each device connected to the network Unless you have a reason to use a different mask set the subnet mask to 255 255 255 0 If the network uses DHCP to assign IP addresses you don t have to enter a subnet mask on each client device For most of us the subnet mask is another of those settings that we have to enter correctly to make the network work properly but we really don t need to know what it means In a large or complex network however you can use subnet masking to separate the network into smaller subsidiary networks or subnets Computers and other network nodes within the same subnet can exchange data more quickly because they don t have to go all the way out to the larger WAN or the Internet and back again to locate one another As you know numeric IP addresses are divided into four groups of numbers each of them within the range from 0 to 255 One part of the address identifies the network and the other identifies a specific com pu
21. and servers are no exception If you re resuscitating an old computer to use as a file server you might be able to salvage the original operating system that ran on that computer but connecting anything earlier than Windows 2000 or Mac OS X to your network could cause more trouble than it s worth If you have some experience with Unix or Linux or if you re willing to learn one of these operating systems might be a better choice because they have up to date features and functions and they won t demand as much processing power or memory as a newer version of Windows a good intro ductory book will help get you started If cost is an issue is cost ever not an issue many Linux and Unix distri butions are available online as free if time consuming downloads or on low cost CDs and DVDs from distributors such as LinuxCD hitp www linuxcd org and The Linux Store hitp www thelinuxstore ca Several versions including CentOS and FreeBSD include server applications along with the core operating system and desktop programs FreeNAS available from hitp www freenas org is also worth considering if you want a simple file server On the other hand if you haven t used Linux or Unix before you might not want to deal with the distractions involved in installing and learning a new operating system at the same time that you re trying to set up a new network Microsoft s Windows Server family and similar products from Apple a
22. operating systems For descriptions and links to additional versions go to hitp www linux com feature 43 1065 MaxiVista Adding a Screen MaxiVista is a slick set of network tools for Windows that allows you to extend your computer s display to one or more additional computers connected to the first computer through your network or to operate two or more computers with the same mouse and keyboard It can also allow you to use the Windows clipboard across two or more computers through the network These tools Other Network Applications 229 230 Chapter 16 aren t for everybody but under certain conditions an extended keyboard or shared controls can be hugely convenient MaxiVista is available in a free demo version from http www maxivista com MaxiVista comes as two programs a server program that runs on the main computer and a client program that runs on each of the secondary machines Except for the network connections that are already in place MaxiVista doesn t require any special hardware All of MaxiVista s controls are on the server the only setting on each client turns the program on or off The server automatically detects each active client and includes controls that you can use to select either an extended desktop or remote control of client computers Multiple Monitors Extending the size of your screen display by adding an additional monitor is one of those things that sounds extravagant but just about everybody
23. re using a plywood panel as your control center mount one or two rows of outlet blocks along the top of the panel or along the side opposite the power strip Keep the outlets evenly spaced and allow enough space to add more outlets in the future Terminate the wires in each network cable on a terminal block with an eight pin RJ 45 socket be sure to follow the color codes and attach a tag to the cable that identifies the location of the cable s other end Use a marking pen or the label supplied with the terminal block to identify each cable on the cover of the block Your goal is to be able to figure out at a glance which terminal block connects to what destination There are two different standard color codes for connecting Ethernet cables to plugs and sockets Use one of the standard color codes T568A or T568B to connect each wire in the cable to the socket inside the terminal block Table 6 2 shows the correct connections It doesn t matter which of the two standards you use as long as both ends of each cable follow the same standard The best approach is to choose a standard and wire every socket in your network to that standard Table 6 2 Wiring for Ethernet Cables and Sockets E AOLLCLLILLLLLLLAALLLULLCGLLCELLLLSL L C amp LLL ULUA ZOLL OUODCZIG LnLILLAULLULLLUUESZIXLLILGSALLAALELGAGGOULIAEL US AA Ou GU ZA Color T568A Pin Number T568B Pin Number Blue Blue White 4 5 Orange 6 Orange White 3 Green 2 Green White 1 8
24. window shown in Figure 12 12 will appear 000 Accounts lt gt Ls 1 Name My Account Short Name ontrols Password Other Acco Mr B gt Admit Verify brd Password Hint Optional C Allow user to administer this computer _ Cancel Create Account 3 ress Book Card Open v Allow user to administer this computer f Login Options tr M id Click the lock to prevent further changes Figure 12 12 Create a new account using this window 4 Type the name and a short name for the new account The short name should be identical to the user s Windows or Linux Unix username 5 Type the user s password in the appropriate field In OS X 10 2 check the Allow user to log in from Windows checkbox and then click OK 7 Close the System Preferences window When an existing user wants to connect to a Mac the user s computer should automatically set up the link in versions later than OS X 10 8 but sometimes you have to instruct the Mac to accept the link This is always required in OS X 10 2 Follow these steps to allow a user to log in from a Windows network l From the Apple menu select System Preferences 2 Select View Accounts 3 Select the account you want to authorize If the computer requests a password type it in the appropriate field 5 Check the Allow user to log in from Windows checkbox The system will instruct you to reset your password 6 Enter you
25. 129 128 129 CUPS printer control program 199 file servers 94 95 96 98 215 file sharing 131 147 150 148 150 firewalls 154 159 155 158 network adapters 73 74 network to Internet connections 115 OpenVPN for 173 remote desktop programs 229 text commands for 43 44 troubleshooting info 247 VPN clients for 172 173 VPN servers for 164 wireless control programs 87 Unlicensed National Information Infra structure U NII 79 updates and patches 185 188 186 187 UPS uniterruptible power supply 61 USB adapters 72 device servers 99 99 100 flash drives 121 ports 4 16 21 70 73 99 192 194 195 201 205 211 212 216 Wi Fi adapters 83 84 84 85 US CERT United States Computer Emergency Readiness Team 189 user accounts 152 c V VGA connectors 218 displays 220 231 video cables 65 66 conferencing 205 237 files 203 205 215 220 messaging 237 outlets 48 49 50 51 output drivers 219 scaling 219 220 servers 7 8 215 VideoLAN 218 Virtual Network Computing VNC 226 229 Virtual Private Network Consortium VPNC 162 Virtual Private Networks VPNs built in support 164 165 165 client software for 165 173 166 172 configuring servers for 163 164 configuring Windows for 165 172 166 172 data tunnels 159 161 functions of 90 159 161 160 161 messaging through 236 methods 161 162 OpenVPN 164 173 overview of and examples 78 90 91 159 174 160 161
26. 13 19 Use the Automatic Updates tab in System Properties to turn on Windows Update 3 Choose an option to set the way your computer will handle new updates In most cases the Automatic option is the best choice but if you re using this computer for programs that require most of the system s processing power such as sound or video recording select the Notify me but don t automatically download or install them option instead 4 Click OK to save your settings and close the System Properties window Automatic Updates loads changes that somebody at Microsoft has flagged as essential to the computer s performance or security but it ignores many others including new versions of device drivers and updates that add or improve other features for Windows and some related programs To find and select these programs follow these steps l Ifyou aren t already connected to the Internet connect your computer now 2 From the Start menu choose Windows Update You can also find a link to this command in Internet Explorer s Tools menu 3 After the Update website confirms that it has installed the software it uses to scan your computer the site displays the Welcome screen shown in Figure 13 20 Click the Custom button 186 Chapter 13 zox 7 x Google XX amp 9 Microsoft Update Search Microsoft com for Microsoft Update Welcome Automatic Home Update E Turned Keep your computer up to date Options Check to see if y
27. 140ms TTL 48 Reply from 72 32 92 4 bytes 32 time 99ms TTL 48 Reply from 72 32 92 4 bytes 32 time 99ms TTL 48 Reply from 72 32 92 4 bytes 32 time 97ms TTL 48 Ping statistics for 72 32 92 4 Packets Sent 4 Received 4 Lost 0 0 loss Approximate round trip times in milli seconds Minimum 97ms Maximum 140ms Average 108ms Listing 4 3 The ping command sends a series of echo requests to a designated address Many books and people will tell you that ping is an acronym for Packet InterNet Groper but Mike Muuss who wrote the original program always insisted that he chose the name to imitate the sound of a sonar system How Computer Networks Are Organized 43 44 Chapter 4 00000 aboard a submarine the sonar system makes an audible ping when an echo pulse returns from a target ping has several uses It can confirm that the distant computer is alive and that your computer s connection is working properly It can also provide a rough idea of the network s performance less time means higher speed ping is also useful for finding a DNS problem if you get a successful ping echo when you enter the target s numeric IP address but not when you enter the domain name the glitch is almost certainly someplace in the DNS system In Listing 4 3 it took about one tenth of a second 100 ms for each test to go from Seattle to San Francisco and back That s a perfectly reasonable amount of time But if one or
28. 165 166 167 168 169 170 171 172 via public networks 173 174 servers 161 162 165 165 167 169 168 viruses troubleshooting 245 VNC Virtual Network Computing 226 229 Voice over Internet Protocol VoIP 54 VPNC Virtual Private Network Consortium 162 VPN Masquerade 164 VPNs See Virtual Private Networks VPNs W wall mounted outlets 59 wall plates 49 49 50 52 55 56 56 67 WANS See wide area networks WANs WAV files 209 210 210 211 web browsers 24 174 webcams cameras 8 204 204 205 237 web hosting services 105 WEP wired equivalent privacy encryption 90 91 174 175 176 179 182 181 183 217 WIA interface 201 wide area networks WANs computer to network connections 117 connections to 24 network to Internet connections 108 109 113 115 overview of 31 32 32 45 Wi Fi wireless fidelity hotspots 77 78 89 links 19 20 194 211 213 215 215 217 224 networks access points 16 53 55 62 80 81 81 85 86 87 90 99 111 113 174 antennas 4 80 82 84 85 configuring 85 86 connection programs 85 87 89 control programs 85 86 87 88 88 designing planning for 54 enhanced extreme systems 78 79 firewalls for 154 159 155 158 172 hybrid wireless networks 89 network interface adapters 81 85 82 83 84 85 87 network standards 78 78 79 operating channels 79 80 80 86 overview of 16 77 78 planning for 50 security methods 54 89 92
29. 17 28 29 47 50 53 54 56 69 75 71 72 125 outlets 53 ports 4 70 74 71 85 97 193 201 216 switches 30 53 53 55 62 80 193 INDEX 255 256 INDEX Exact Audio Copy 208 Extensible Authentication Protocol EAP 182 external controllers 204 205 external printer servers 792 192 193 extreme systems 78 79 F faxing devices 199 201 200 F connectors 218 fiber optic links 6 field replaceable unit FRU 82 File and Printer Sharing for Microsoft Networks 196 196 file servers backup files 100 104 101 103 104 choosing 94 home usage of 105 NAS network attached storage devices 93 95 97 98 98 100 108 overview of 24 93 94 sharing permissions 96 97 97 software systems for 94 96 96 97 99 98 99 storing files on 96 97 USB device servers 99 99 100 file sharing compatibility issues 131 computer to network connections 120 dialogs 140 140 Linux 131 147 150 148 150 Macintosh OS X 131 134 135 143 147 144 146 media sharing 143 overview of 5 5 131 132 passwords and privacy 133 136 134 143 permission levels 141 143 printer sharing 7 143 196 196 199 198 199 Server Message Block SMB protocol 131 143 145 147 146 150 Simple File Sharing 752 132 133 136 Unix 131 147 150 148 150 usernames 140 141 145 Windows Vista 131 136 143 137 142 Windows XP 131 132 132 136 134 135 file storage servers 96 97 file synchronization 232 File
30. 255 0 Gateway address 192 168 0 1 apog Figure 11 16 Use the Gnome network Properties window to configure a network connection without a DHCP server Figures 11 17 and 11 18 show the KDE Control Module utility included with PC BSD To change the configuration settings select the adapter connected to the network and click the Configure button Configure KDE Control Module Changes in this section requires root access Click the Administrator Mode button to allow modifications Devices DSL PPPoE Local Network Adapters Ej xl0 3Com 3c905C TX Fast Etherlink XL v Display system tray icon Configure Device Status Address IP 192 168 1 102 Netmask 255 255 255 0 MAC Address 00 01 03 30 54 0b Status active System wide configuration settings DNS 2 Gateway is IPv6 gateway Administrator Mode bd Figure 11 17 The KDE Control Module utility includes network settings for each network adapter xlo configuration e amp General Advanced Info Network address configuration O Obtain IP automatically DHCP Assign static IP address let Netmask 255 255 255 0 C Disable this network device OK Apply Close Figure 11 18 The KDE configuration window for each network adapter includes settings for DHCP IP address and the subnet mask Netmask Other desktop environments might use different configuration utili
31. 400 GHz 2 483 GHz Figure 8 1 Wi Fi signals use 11 separate overlapping channels Notice that channels 1 6 and 11 do not interfere with each other Access Points Chapter 8 Every Wi Fi network must have at least one access point Wi Fi access points or base stations are radio transmitter receivers transceivers that send and receive data by radio and exchange that data with a wired Ethernet network You can think of an access point as a router between a Wi Fi network and a wired LAN Most access points have one or two short antennas attached to the back panel some also have a connector that can mate with a cable from a separate antenna Separate antennas are useful because they can increase the access point s signal strength and sensitivity but they re usually not necessary in small indoor home or small business networks There s more about antennas later in this chapter Wi Fi access points are often combined in a single unit with cable or DSL modems gateway routers or Ethernet switches If your network includes both wired and wireless connections you might want to consider a combined device which is often less costly than two separate boxes Figure 8 2 shows a combined access point Ethernet switch and router Indicator lights on the front of this device show power wireless activity and data moving to or from each wired network node A single 802 11g or 802 11n base station should provide more than enough signal coverag
32. 5of5 network connections either do not have Windows Firewall enabled oc they are enabled with exceptions Firewall What Result det t d 9 Automatic Updates are automatically downloaded and installed on this computer Updates What L File All hard drives 4 are using the NTFS file system System What Result det Ld Restrict Computer is properly restricting anonymous access Anonymous Administrators No more than 2 Administrators were found on this computer Additional System Information Score Issue Result udting Enable auditing for specific events like logon logoff Be sure to monitor your event log to watch for unauthorized access sees Some potentially unnecessary services are installed 9 Shares 16 share s are present on your computer zi Print this report D Copy to clipboard o _oK Figure 13 22 Microsoft Baseline Security Analyzer finds potential security problems and offers instructions for fixing them Controlling Your Own Users As manager of your home or business network remember that you re responsible for the security of the whole network and all the computers connected to it Whenever it s practical do whatever you can to encourage all your users to pay attention to security Even if it seems easier to run their computers wide open without proper security measures you are responsible for convincing them to keep their computers safe Denial of Service Attacks A denial of service Do
33. 7 Brown N 0 00 0o NORA Brown White Follow these steps to connect a CAT5 CAT5e or CAT6 cable to an Ethernet socket 1 Allow about a foot of slack and cut off the excess cable 2 Remove about two inches of the cable s outer jacket Be sure you don t nick any of the internal wires with your stripping tool 3 Separate the four pairs of wires that extend beyond the jacket but don t untwist the individual wires 4 Follow the instructions supplied with the connector to direct each wire to the correct slot Be sure the jacket extends into the back of the connector 5 Use a punch down tool to insert the two wires closest to the back of the connector into their respective slots 6 Insert the wires from the other three pairs into the correct slots Don t untwist the pairs any more than is necessary 7 Double check to confirm that each wire is in the correct slot according to the color code you are using 8 Ifyour punch down tool doesn t automatically cut off excess wire use a wire cutter to trim each wire 9 Ifthe RJ 45 socket came with a dust cover snap it into place over the wires 10 Insert the socket into the terminal block or the wall plate from the inside of the block or case Adding a Telephone When you re trying to solve a problem with your network connection it s often helpful to have a telephone next to the control panel so you can talk to a technical support person while you re l
34. 92 174 184 175 178 181 sniffers 178 179 249 topologies 27 28 28 webcams 205 wiring methods 16 18 Network Setup Wizard 118 122 119 120 121 Network Stumbler 179 Network window 125 Newegg com 57 Nintendo Wii 220 221 NIST Cerberus 173 NNTP network news 158 nodes 14 48 50 noise 13 17 nondirectional antennas 85 Novell 95 null modems 19 79 numeric IP addresses 36 37 42 109 110 0 OEM original equipment manufacturer 85 95 Ogg Vorbis files 270 omnidirectional antennas 85 ones and zeroes 10 10 See also Internet Protocol IP addresses online virus scans 245 OpenBSD 159 164 173 OpenDNS 41 114 open source operating systems 96 OpenVPN 164 173 Opera 24 operating channels Wi Fi 79 80 80 86 org 40 original equipment manufacturer OEM 85 95 outlet blocks 59 60 60 outlets cable TV 48 49 data 48 56 56 57 59 60 67 68 electrical 48 50 49 52 52 55 56 59 Ethernet 53 telephone wall 48 49 51 video 48 49 50 51 wall mounted 59 P Packet Filter PF 159 Packet Internet Gopher 43 packets 11 13 72 Panda ActiveScan 245 parallel ports 4 16 192 792 194 parallel signals 10 parity bits 13 passwords 90 133 136 134 148 152 154 154 205 patch cords 56 57 patches and updates 185 188 186 188 PC card adapters 82 83 83 PC Express Cards 82 83 PCI expansion cards 72 72 84 204 PCMCIA sockets 73 82 peer
35. 96 kHz per second WAV files so you ll have to play them in another program such as Audacity or Sound Forge Converting from Analog Sources If you want to distribute music and other recordings from LPs and other analog media such as cassettes old 78 rpm discs and reel to reel tape through your network you must convert them to digital audio files first This conversion is more time consuming than ripping CDs but it can be rewarding if you have some great old records that are not available in any other format If you plan to transfer a lot of analog media to digital files it s worth the extra cost to use a better analog to digital converter than the one built into your computer Professional studio quality converters can cost hundreds or thousands of dollars but less expensive devices such as the ones made by E Mu M Audio and Edirol among others will give you considerably better performance than consumer grade sound interfaces Remember that the sound of your digital copy won t be any better than the sound coming from the analog original Before you make a copy be sure to clean the dust and grit from your LP and make sure the needle on your record player is in good condition Use alcohol or some other head cleaner to remove the gunk from the face of the heads before you try to play cassettes or reel to reel tapes Audio Clients In a home network the other half of a music distribution system is a music client or audio clie
36. 98 159 164 172 173 BSSID 177 179 builtin Ethernet window 725 builtin printer servers 194 bulk cables 56 C cable modems 110 cables bulk 56 CAT5 CAT5e CAT6 data 50 56 57 66 coaxial 17 65 for combination boxes 33 DVI 219 220 Ethernet 15 47 53 56 60 60 66 66 77 192 jumper 56 overview of 33 56 RG6 U 65 troubleshooting 242 twisted pair 15 15 video 65 66 cable TV connections 32 64 99 outlets 48 49 cameras webcams 8 204 204 205 237 CardBus 73 Carrier Sense Multiple Access with Colli sion Detection CSMA CD 14 CAT5 CAT5e CAT6 data cables 50 56 57 66 CBS 3 CDs music 208 209 211 CentOS 95 CHA 1 Connected Home Appliances standard 223 chatrooms 237 checksums 13 Cisco 161 164 client firewall programs 157 158 159 clients audio 211 212 213 clients and servers 23 25 25 clones 100 coaxial cables 17 65 collisions 14 18 com 39 40 combination boxes 33 commands See network commands communication channels 3 11 complete images 100 compressed audio files 209 Computer Supported Cooperative Work 233 computer to network connections See network connections conferencing remote 205 237 Connected Home Appliances CHA 1 standard 223 control centers See networks control centers controller cards 204 conversions audio 206 207 209 211 converters analog 206 207 209 211 212 audio 206 207 209 211 power 61 TV video 219 coop 40
37. Cable Connection ssssssse ee 64 Terminating the Network Cables sss 66 Pe SDN m 67 Tabletop Control Centers for Small Networks sss 67 7 ETHERNET NETWORK INTERFACES 69 Builtinto the Motherboard 5 orte locet teo ee slb ous Fosb be ce aea 70 Setting the BIOS Utility esses eme 71 Adding a Network Interface to an Old Computer sss 72 Internal Expansion Cards sess eene 72 USB Adapters 2 eter tee ertet en ae carva costae ene pate 73 Network Adapters for Laptops 73 Finding the Driver Software for Your Adapter 74 Status Lights on Network Adapters sss 75 Vill Contents in Detail www allitebooks com 8 WI FI NETWORKS 77 Types of Wi Fi Networks me eee nene 78 Operating Channels 24 1 5 Hardt tees t b ele Han oerte eto Perd erbe gta 79 f rrsidel cc LEE 80 Network Interface Adapters ccccecseecseeeseeeeeecseeeseseseeereeseseseseeereeeteeeeseseeeeeeeees 81 Adapters Built into Laptops esss ee 81 pereo m PME 82 USB Adapters 1 c coepere nep d ekle e ue eni pee tee s 83 uela n cM 84 Antennas erede iiti Meas vans PORE E PE Er eee h Reg de ERAT e eee IE e e ee es 84 WiFi Control Programs 3 2 ente petet e EG QU D PPAR Ee Ms 85 Access Point Configuration Programs sssssssseee ee 85 Wireless Connection Programs sse eme eem ens 87 Hybrid Wired Wireless Networks
38. Classic Start Menu select Settings Network Connections The Network Connections window shown in Figure 11 7 will open Network Connections 5 xl File Edit View Favorites Tools Advanced Help QBack 7 Ov 7 P Search i Folders i gt gt X 9 3 Address s Network Connections e a ei Network New 1394 America Setup Connecti Connection Online Wizard i i 91 Dial up Internetvia Local Area Connection MSN Connection 1 7 objects Z Figure 11 7 The Network Connections window shows all of your computer s network profiles 2 Your wired connection profile is the one called Local Area Connection and sometimes includes a number The number is usually 1 as shown in Fig ure 11 7 but if you have added or deleted additional profiles some other number might be used If you re using a Wi Fi or other wireless network connection the network profile will be called Wireless Network Connection Open the Local Area Connection and click the Properties button or open the Wireless Network Connection profile and click Change Advanced Settings A status window similar to the one shown in Figure 11 8 will open Local Area Connection 1 Propane d 4 E NW Link NetBIOS i F7 NWLink IPXISPXINetBIOS Compatible Transport Protocc i4 7 Microsoft TCP IP version 6 sa W Internet Protocol TCP IP Figure 11 8 The Local Area Connection status window shows information about your network connection Scroll down
39. Denial oF Service Altacks eee eere e eie S 189 emp e 189 X Contents in Detail 14 PRINTERS AND OTHER DEVICES ON YOUR NETWORK How to Connect a Printer to Your Network eee External Printer Servers ccccccccccceseeeececccceusueecececceusaueseeseceeeuaseecess Wi Fi Printer Servers c0 cc0ccccssccescccsssccsecessscesvectevcesccatevccsvesevvcsesseee Built In Printer Servers ssssee ee e emememes eren eis Automatic Printer Switches seeseeeeee emen enne Using a Computer as a Printer Server CUPS The Common Unix Printing System sss AllinOfie Devices inb occ e Mee cec tte cor dee roe deese ett osa 15 OTHER THINGS YOU CAN CONNECT TO YOUR NETWORK AUDIO VIDEO HOME ENTERTAINMENT AND BEYOND Using a Microphone and Camera with Your Network ssseee Internal and External Controllers s Networked Cameras and Microphones Home Entertainment Networks sssssse eene emere Music Through a Home Network sssssssse eem A dio Servers insiet ene de ade eme dies Audio Clients etico totis eneiee ce eret ttbi ob RE SE b ens Video Through a Home Network sssssse eee Vide6 Servers sonion iu ea at cater ter Piae e Pope P apre en TiVo and Other Digital Video Recorders ssssee Playing Video on a Computer sssss e Connecting a TV to Your Network sssss
40. Documents My Music My Pictures and other folders in drive letter Documents and Settings lt username gt To assign a folder or disk drive to Level 1 access follow these steps From the Windows desktop open My Computer Select Documents and Settings and then select the username folder 3 Ifthe folder you want to assign to Level is not visible in the My Com puter window open the drive or folder that contains that folder Right click the drive or folder icon 5 Select Sharing and Security from the pop up menu The Properties win dow shown in Figure 12 2 will appear Sharing Files Through Your Network 133 134 Chapter 12 My Music Properties xl General Sharing Local sharing and security Ys To share this folder with other users of this computer only drag it to the Shared Documents folder To make this folder and its subfolders private so that only you have access select the following check box Make this folder private Network sharing and security To share this folder with both network users and other users of this computer select the first check box below and type a share namo Share this folder on the network F Ala ork users to chang Learn more about sharing and security V rrelw 4 Windows Firewall is configured to allow this folder to be shared with other computers on the network a eo Figure 12 2 Check the Make this folder private checkbox to restrict access to
41. FTP default data 21 FTP File Transfer Protocol 23 Telnet 25 SMTP outgoing mail 37 Time 53 DNS Domain Name System 70 Gopher 79 Finger 80 HTTP web server 88 Kerberos 110 POP3 incoming mail 119 NNTP network news 1863 Microsoft MSN Messenger 5190 AOL Instant Messenger 7070 Real Audio and Video Firewall Software A wireless gateway firewall at the interface between the access point and the wired part of your LAN will keep intruders from using your network to reach the Internet and a firewall at the Internet connection will turn away attempts to connect to your network from the Internet but a wireless network still needs one more form of protection If somebody gains access to your wireless LAN without permission you want to keep them away from the other legitimate computers on the same network so each network node needs a client firewall program Client firewalls perform the same functions at a computer s network interface that a LAN or enterprise firewall performs for the entire network a client firewall detects attempts to connect to TCP service ports and rejects them unless they match one or more of the firewall program s configuration settings Several good firewall products are available as shareware and others are free to noncommercial users It s easy to try them on your own system and choose the one you like best ZoneAlarm hitp www zonealarm com and LANguard hitp www languard com are both well reg
42. GO Control Panel gt Printers File Edit View Tools Help Documents Status Comments Location Microsoft XPS Document Samsung ML 1740 Series p Soe 2 Figure 14 6 The Add a printer icon is on the toolbar directly above the Printers window CUPS The Common Unix Printing System CUPS is a printer control program for Unix and Linux systems that converts page descriptions from application programs such as a word processor or a web browser to the specific instructions used by individual printers If printing from your Unix or Linux distribution requires complicated command line instructions CUPS can provide an easier solution look for a free download from Attp www cups org A CUPS driver for Windows is also available as an extension to the PostScript driver supplied with Windows It s available at http www cups org windows CUPS can print to a printer connected directly to your own computer or through a network to a printer server All in One Devices Most offices perform several different paper handling activities copying printing scanning and faxing All of these activities use some combination of the same core functions so it often makes sense to combine several activities in a single machine that can send a digital file or scanned image to either paper or another digital file The category of device that combines these functions is called rather grandly an all in one device or simply an all in one An al
43. Internet Protocol VoIP telephones smart phones and other portable devices If you decide to include one or more Wi Fi access points in your network mark their tentative locations on your floor plan In most cases a single access point can exchange data with computers and other devices within about 300 feet 100 meters so the exact location is not critical The best location is often either in the network control center or on the floor or a table next to a computer in a fixed location For detailed information about installing Wi Fi access points and connecting Wi Fi devices to your home or office network see Chapter 8 With your network floor plan more or less complete you re ready to install the control center and string Ethernet cables to each room The next chapter will tell you how to do that job INSTALLING THE NETWORK CONTROL CENTER AND ETHERNET CABLES and other devices to the network through cables or wireless links your network must have some kind of control center that includes one or more hubs or switches for your wired Ethernet connections an access point for Wi Fi or both If you plan to connect your LAN to the Internet the control center must also include a gateway router and a modem This chapter explains how to assemble a control center and run cables between the control center and the computers game consoles printers and other devices that make up your network Connectors Wall Plates and Surface
44. Options Next Backup Time Machine Time Machine keeps Hourly backups for the past 24 hours Daily backups for the past month OFF EN jJ ON Weekly backups until your backup disk is full 1 Click the lock to prevent further changes Figure 9 9 If you have a new Mac turn on Time Machine to automatically create backups Before you trust your critical files to any backup program run some tests to confirm that the program can accurately restore those files including the metadata embedded inside them Some Mac backup programs designed for earlier versions have trouble dealing with OS X files Linux and Unix Backups Linux and Unix users have a wide choice of backup programs including sev eral that can originate the backup process from either the server pulling backup data from client computers or from individual client computers pushing the backup files to a server The Linux Online website includes an up to date list of backup programs at http www linux org apps all Administration Backup html Distributions with graphic environments such as Gnome and KDE usually include at least one graphic backup program One possible backup solution on computers running Linux Unix or Mac OS X is to use rsync over SSH to an external system and schedule it via cron This doesn t have a nice graphical front end but it gets the job done securely and efficiently because rsync does not copy bytes across the network th
45. PDA personal digital assistant or a mobile Internet device such as a BlackBerry or an iPhone you can often connect it to the Internet via Wi Fi by simply turning it on Many home and small business networks use a combination of Ethernet and Wi Fi the Wi Fi base station doubles as a connection point for Ethernet cables so the same LAN includes both wired and wireless nodes Chapter 8 contains information about installing and using Wi Fi network links Powerline Networks Chapter 2 In a powerline network computer data moves through a building s existing electric wiring Each computer connects through a parallel port a USB port or an Ethernet port to a data adapter that plugs directly into an AC wall outlet The same power transformer that feeds your house wiring also isolates your data network from your neighbors The most widely used standard for powerline networks is called HomePlug The greatest advantage of HomePlug and other powerline networks is that the wires are already in place Every AC wall socket in the house can double as a network connection point It s also more secure than Wi Fi and it can reach greater distances than a Wi Fi network with just one base station Wi Fi signals are often blocked by thick walls and other obstacles that make no difference to a powerline system NOTE You must plug all your powerline adapters directly into wall outlets Surge protectors and powerline conditioners often absorb powerline net
46. Transfer Protocol FTP 39 157 158 Finger 158 Firefox 24 firewalls 90 91 154 159 155 158 164 172 176 firewall servers 24 FireWire ports 4 21 205 211 fixed IP addresses 37 38 109 118 FLAC Free Lossless Audio Codec files 210 flash drives 1 3 120 217 floor plans 47 48 48 54 55 59 floppy disks 3 4 FM radios 214 Folder Options window 132 132 frames 11 13 248 FreeBSD 95 98 173 FreeFileSync 232 Free Lossless Audio Codec FLAC files 210 FreeNAS 95 98 98 FreeNX 226 FreeS WAN 164 173 FRU field replaceable unit 82 FTP File Transfer Protocol 39 157 158 full duplex mode 30 G Gadu Gadu 235 game consoles 220 222 game servers 24 gateway addresses 109 114 115 gateway routers 6 6 32 109 110 Gigabit Ethernet networks 14 15 29 56 72 Gmail 105 Gnome 104 127 127 128 128 147 149 148 GoodSync 232 Google Talk 234 235 Gopher 158 gov 40 gramophones 206 207 207 graphical user interface GUI 150 guest accounts 152 GUI graphical user interface 150 hackers 82 92 157 249 handoffs 177 handshaking 13 14 HDMI See High Definition Multimedia Interface HDMI HDTV screens 219 220 headers 11 13 12 Hewlett Packard HP 95 hex encryption keys 180 181 181 hidden networks 179 High Definition Multimedia Interface HDMI 217 cables 219 220 high gain directional antennas 85 high speed modems 109
47. What else happened Have you noticed any other problems or unex pected events Has another network user experienced a similar problem at about the same time Is this a new problem Have you ever experienced this problem or something similar before look for Simple Solutions First Look for easy solutions before you start to tear apart hardware or run complex software diagnostic routines Nothing is more aggravating than spending several hours running detailed troubleshooting procedures only to discover that restarting a computer or flipping a switch is all that was needed to fix the problem Restart Everything The first thing to try when an otherwise unexplainable problem occurs is to turn off each network component one at a time wait a few seconds and then turn it back on again Sometimes that s all you need to do to clear a program or a chunk of memory that is stuck on the wrong setting and return it to the correct value If possible use the operating system s shut down process to turn off the computer in an orderly manner don t use the power switch or reset button unless the computer won t respond to a mouse or keyboard command Don t turn off your computer until you have copied the text of amy error messages on the screen Sometimes the same problem will produce a different message after you restart or none at all and the text of the original message might be a useful troubleshooting tool When you restart a computer don t
48. XXX XXX you have entered for this network adapter is already assigned to another adapter 1 get the error message LAN Connection A network cable is unplugged 1 get the warning Limited or no connectivity The problem occurs only on a wireless connection The Networking Wizard does not run to completion Internet 80 Al Figure 17 1 The Windows Network Problem Solver is an excellent interactive trouble shooting tool This screen image shows only a small portion of the page scroll down for additional information and instructions Software for Troubleshooting Chapter 17 Several software programs can gather and display useful information when you re trying to understand what s happening inside your network These programs are available as free or trial downloads so you don t incur a cost when testing them Network Magic Network Magic http www networkmagic com provides a graphic display of the devices connected to a LAN as shown in Figure 17 2 and a central control point for adding new network devices or changing the existing network configuration It can also perform some basic troubleshooting tests and automatic repairs Protocol Analyzers Microsoft Network Monitor go to Attp wwuw microsoft com downloads and search for Network Monitor and Wireshark http www wireshark org are free protocol analyzers that capture and display data as it moves through your network In other wo
49. You will find more information about VNC later in this section Windows Remote Desktop Windows Remote Desktop transfers control of a client computer to a host The host mirrors the screen display from the client and the host s mouse and keyboard control the programs running on the client When Remote Desktop is active the client computer displays a blank screen and doesn t respond to keyboard or mouse input until the host releases control Remote Desktop makes the person running the host computer a sort of superuser who can take control of a client computer so several controls are built into the system that limit this kind of access First the user of the client must set the computer to accept Remote Desktop access and second the person running Remote Desktop on the host computer must have an account usually with a password on the client computer In other words if you turn off Remote Desktop on your computer other people can t use it without your permission In Windows XP the remote access tool is called Remote Access in Windows Vista it s known as Remote Desktop Computers running Windows Vista Starter Windows Vista Home Basic Windows Vista Home Basic N or Windows Vista Home Premium won t accept incoming access but you can use Remote Desktop to take control of another computer running some other version of Vista Windows XP Home Edition won t accept access from any Windows Vista machine Configuring Windows for Remote Deskt
50. a Wi Fi access point Photo courtesy of Lantronix Figure 9 5 The Lantronix UBox connects external disk drives and other USB devices directly to your network Apple s AirPort Extreme Whether or not you re using Macintosh computers in your network Apple s AirPort Extreme product can be an inexpensive alternative to a full size file server Along with its functions as a DSL or cable gateway router an Ethernet switch and a Wi Fi base station the AirPort Extreme also has a USB port that can connect an external hard drive directly to your network To use more than one external hard drive connect them to the AirPort Extreme through a USB hub Figure 9 6 shows the rear panel of an AirPort Extreme USB WAN Ethernet port port ports E igi o cm e NES ES Photo courtesy of Apple Figure 9 6 AirPort Extreme can connect a USB hard drive directly to your network File Servers 99 100 Backing Up Files to a Server Chapter 9 There s more than one way to back up files to a server You can run a backup program on the client machine and specify a drive and folder on the server as the backup storage location or you can originate the backup from the server and select files on one or more clients as explained earlier client computers are the ones that receive services from a server Before you create your backups you must decide exactly what you want to accomplish Several different kinds of backups are possible
51. a general overview of networks and the things you can do with them In later chapters you will learn how networks handle digital data how different kinds of networks move that data from one place to another and how the equipment at the core of most networks hubs routers modems and other devices works Next I ll introduce the important concepts of clients and servers and tell you how to design and install simple wired and wireless networks how to connect the local network to the Internet how to build security into your network and how to use your network for music and video along with computer data And finally the last chapter of the book offers advice about troubleshooting and describes some useful tools that might make life a bit easier when it becomes necessary to find and fix a problem When you have a network in your home or small business all the com puters connected to the network will become more flexible and more useful Your new network will change the way you use your computer within a few weeks or less you will definitely wonder how you got along without it When you and the other people connected to your network find yourself using it without thinking about the network you and I will both have met our objectives Introduction xvii HOW A NETWORK WILL IMPROVE YOUR LIFE employer or your spouse bring a computer into your office or your home and every thing is right there word processing files finan
52. a terminal block to each end and pre built cables for patch cords and for connections between wall outlets and network devices Patch cords are widely available in office supply and electronics stores but they re often four or five times more expensive than the identical cables sold through industrial electronics suppliers and online sources such as Jameco Attp www jameco com Cyberguys http www cyberguys com and Newegg com http www newegg com A 3 foot cable should not cost 8 or 10 There s no reason to pay more for premium patch cables any cable that meets the CAT5e specification will do the job This piece of advice will probably save you more money than you paid for this book In buildings with raised floors or dropped ceilings it s often convenient to run your data cables through the plenum space above the ceiling or under the floor However fire regulations often require special plenum cable that won t burn easily and won t produce toxic fumes Plenum cable is more expensive than regular bulk Ethernet cable and it s more difficult to use because the jacket is heavier and less flexible but there s no difference in its data handling performance When you re shopping for cable you might find boxes or spools of plenum cable next to regular CAT5e cable Sometimes the only difference is a single line on a label Unless you have a specific need for plenum cable don t waste your money on the more expensive st
53. additional wiring and equip ment in the future e Itshould not be adjacent to the fuse box circuit breaker box or other electrical panel AC power wiring must be kept separate from network telephone and video cables to prevent interference and to comply with the National Electric Code After you choose a place for the control center note its location on your floor plan Home Run Wiring When you have identified the locations of your network connection points and found a place for the control center you can plan the routes for your network cables The preferred method for network wiring is called home run wiring because each cable runs home to a central hub or switch The alter native which is more practical for telephone and video wiring than for data networks is point to point wiring that uses long cable runs that connect to each outlet through a splitter as shown in Figure 5 3 Designing Your Network 5 Desktop computer Desktop computer Tower PC Telephone service entry Telephone Telephone Desktop computer i li F S Telephone s Telephone Tower PC Telephone EN ae Telephone Figure 5 3 Home run wiring left is best for data networks telephones and video can use either home run wiring or point to point networks right 52 Chapter 5 If you ha
54. an Ethernet port or jack that mates with the plug on an Ethernet cable Both the plug and the socket follow a standard called R 45 that specifies the size and shape of the connectors and the signals that move through each of the eight pins RJ stands for Registered Jack RJ 45 connectors are similar to the six pin RJ 11 plugs and sockets used on telephones but the RJ 45 is slightly larger to allow for the additional pins Figure 7 1 shows both an RJ 45 Ethernet plug and an RJ 11 telephone plug E X Ww F168630 CSA wu r Figure 7 1 An RJ 45 data plug left has eight wires an RJ 11 telephone plug right has four or six wires In addition to the port itself an Ethernet interface also includes some internal hardware that converts the data in both directions between the format that the computer s central processor can handle and the format used by the network This hardware can take several forms It can be e On the computer s main circuit board the motherboard e A printed circuit card that mounts inside the computer e APC card that plugs into a laptop computer e An external unit connected to the computer through a USB cable Almost all the computers built within the past few years have built in Ethernet ports On desktop and tower computers the RJ 45 jack is on the back of the case as shown in Figure 7 2 On laptop computers the Ethernet port is usually on either the back or the side of the case If your compute
55. and take action to make it stop When this happened to me I used Wireshark to find the numeric IP address of the computer that was originating the bogus messages and a whois program to identify that computer s owner then I sent an email explaining the problem and asking them to fix it The data stream stopped within an hour A network sniffer can also identify a device within your own network that becomes infected or has some other problem that interferes with proper operation By running the sniffer program on more than one computer or even inserting a sniffer at a router a modem connection or other interface point you can often isolate the source of a problem You won t use a protocol analyzer very often which is probably okay because it s a complex and tedious process But when you need to know what s moving through your network an analyzer can give you information that you won t find anywhere else Troubleshooting 249 Microsoft Network Monitor 3 1 i Flags SePort 7155 OtPort HTTP 80 Len 0 Seq 161179712 Ack 1113806802 Win 30492 scale fac HTTP Request GET static feedroom com t_assets 20081002 d6173tac58ad5 0518043642252b5ae4bocBcoe3 Jpg SIKPOIteHTTINSUL OstPort ET inn eoi Adee 211187707 Win 5840 scale m DstPorts HTTP 80 Len a DESKTOP HTTP 80 OstPort 7157 Len 0 Seq 1 108286578 Ack 3398554873 win 5840 scale fa 72 246 51 15 CP e HTTP 80 Len 0 Seq 3398554873 Ack 1108286579 Win 3
56. change to all subfolders and their contents option Samba Samba is a suite of programs that uses SMB to allow file and print sharing from non Windows operating systems including Linux Unix and several others If it s not included with your Linux or Unix package you can download it from Attp samba org Samba itself uses text commands rather than a graphical user interface GUI but several add on GUI interfaces are available at Samba s website Unless the people using Linux or Unix on your network are comfortable using a command line shell you will want to install at least one of these GUIs along with Samba Using Shares Chapter 12 Shared folders and directories which are two names for the same type of resource are a basic networking tool Any time two or more people want to collaborate on a project they can share access to the documents and information files by creating a project share and allowing any member of the group to work on those files Your computer displays shared folders and other network resources just like files and folders stored on your own computer so where the file is actually stored doesn t matter you can place a shortcut to a share on your desktop and open a shared document or other file with a couple of mouse clicks just as if the file was stored on your own computer NETWORK SECURITY Any time you operate a network you must protect it against intrusions from outsiders and damage caused by
57. choice Unless your family operates like a business your home network probably needs a different set of features from the ones used by a business central storage backup and maybe web and email hosting But you probably won t use other common business server features such as database services and project management Microsoft s Windows Home Server is optimized for home rather than business use so this product might be a better choice for your household network Windows Home Server is available already installed on server computers from HP and other manufacturers and Microsoft also offers an OEM version that you could install on an existing computer if that computer exceeds the minimum requirements which are considerably more than those needed for a Linux server However that version doesn t include any kind of Microsoft support so you re on your own when you have trouble installing or using it The OEM version can be difficult to find through local retailers but plenty of web and mail order suppliers will be happy to sell you a copy File Servers 95 96 For mixed networks that include computers using more than one operating system Samba hitp www samba org is an excellent choice It s a well established open source and therefore free cross platform file sharing program Figure 9 1 shows the control console screen for Windows Home Server The minimum requirements for Windows Home Server are listed in the WHS Getting Started
58. cmd In Mac OS X select Applications gt Utilities and the Terminal program If you re using Linux or Unix use a command prompt or an XTerminal IPConfig The IPConfig tool displays detailed information about your computer s current LAN and Internet connection as shown in Listing 4 1 How Computer Networks Are Organized 41 C gt 1PConfig Windows IP Configuration Ethernet adapter Local Area Connection Connection specific DNS Suffix IP Address ee ee Subnet Mask 2 ee Default Gateway domain actdsltmp 1 192 168 1 100 1 255 255 255 0 1 192 168 1 1 Listing 4 1 The IPConfig tool displays the status of a computer s network configuration In this example Connection specific DNS Suffix is an address assigned by a DHCP host This address is often an arbitrary name used internally within the network but if your computer is connected directly to the Internet it might be your computer s DNS address If you try to connect to a domain name without a suffix such as example rather than example net the network will assign this suffix to the address when it sends it to a DNS server The IP Address is the numeric address of this computer within the LAN or WAN The Subnet Mask tells the network which parts of the numeric address identify individual computers and the Default Gateway is the numeric address within the LAN of the gateway router that connects your LAN to the Internet For more
59. computer printer or other network device that mates with an Ethernet cable to connect the device to a network The instruction manual or the label on every piece of Ethernet compatible equipment should tell you which type of connection it uses Twisted pair cables are bundles of wires in which each pair of wires is twisted together as shown in Figure 2 3 Because data normally moves in only one direction through each pair of wires a 10Base T or 100Base T network connection uses two pairs one for each direction The most common Ethernet cables include a total of eight wires in four color coded wire pairs so you can use the remaining wires as spares Figure 2 3 A typical Ethernet cable contains four twisted pairs of color coded wires Most of the remaining chapters of this book are dedicated to features and functions of Ethernet networks Types of Network Connections 15 16 DEALING WITH OTHER MOSTLY OBSOLETE WIRED NETWORKS Ethernet is by far the most widely used type of LAN connection but if you re using older equipment you might occasionally find a computer or other device that uses some other type of network structure Many of those older networks require special equipment and experienced network technicians but the rest of us don t have to run away from them If you have inherited a working network the best thing you can do is to leave it alone It has probably been working without any problems for many years and you
60. con nection This name will appear on desktop shortcuts to this connection Click the Next button 6 In the Public Network window shown in Figure 13 8 select the Do not dial the initial connection option because you don t need to connect through a telephone line Click the Next button New Connection Wizard Public Network Windows can make sure the public network is connected first Figure 13 8 In a wireless network the VPN does not require a dial up connection 7 In the VPN Server Selection window shown in Figure 13 9 type the host name or IP address of the VPN server New Connection Wizard VPN Server Selection Whatis the name or address of the VPN server example com Figure 13 9 The host name or IP address identifies the VPN server at the other end of the wireless link 8 Click the Next button and then the Finish button to complete the wizard Network Security 167 168 Chapter 13 10 In Vista follow these steps Open the Control Panel Select the Network and Sharing Center In the Tasks list on the left side of the Network and Sharing Center shown in Figure 13 10 select the Set up a connection or network option A Choose a Connection Option window will open Blo Gort Network and Internet Network and Sharing Center f Search 5 File Edit View Tools Help lt e Network and Sharing Center View full map i Ls e TOWER Local Internet Thi
61. copying devices 199 201 200 country codes domain name 39 40 CSMA CD Carrier Sense Multiple Access with Collision Detection 14 CUPS printer control program 199 Cyberguys 57 D data cable color codes telephone lines 65 circuitterminating equipment DCE 18 19 communications equipment DCE 18 19 entry remote 224 networks 4 outlets 48 56 56 57 59 60 67 68 packets 11 13 12 terminal blocks 52 52 transfer speeds 14 15 tunnels 159 161 data file only backups 100 data terminal equipment DTE 18 19 DCE data communications equipment or data circuit terminating equipment 18 19 decoders audio video 218 default gateways 42 43 114 118 246 Dell computers 94 demodulation 6 108 denial of service DoS attacks 189 designing networks 47 54 48 49 52 53 destinations 206 207 device drivers 74 75 DHCP See Dynamic Host Configuration Protocol DHCP dial up modems 109 dictionary attacks 183 digital audio files See audio files digital conversions 209 digital data streams 204 205 digital media receiver DMR 143 digital to analog conversion 206 207 211 digital video recorder DVR 216 217 digital visual interface DVI 218 DirSync Pro 232 Display Properties setting 231 251 D Link programs 180 181 781 216 switches 64 dm crypt 185 DMR digital media receiver 143 domain names See also Internet Protocol IP addresses country codes in 39 40 subdomain 39 top
62. display the current settings Press the button again to save the configuration values The Test Con nection screen will appear Press the button to test the connection After approximately a minute or less the PlayStation will display either a Succeeded or Failed message If the test was successful the PlayStation is ready to run multiplayer games if it fails the PlayStation will provide instructions for fixing the problem Connecting a Wii Nintendo s Wii console requires an optional Wii LAN Adapter Model number RVL 015 to connect to a network Follow these steps to connect a Nintendo Wii to your LAN 1 10 11 Turn off the Wii console and plug the LAN Adapter into the console s USB port Run an Ethernet cable from the LAN Adapter to your network router or hub Turn on the Wii console From the main menu click the Wii button at the bottom left A screen showing a Data Management box and a Wii Settings box will appear Click the Wii Settings box The System Settings screen will appear Click the blue arrow at the right side of the list of options to move to the second of three System Settings menus Click the Internet button The Internet screen will appear Click Connection Settings A list of Connection Settings options will appear Select an empty connection slot with None shown as the connection type Select either Wireless or Wired Connection as appropriate for your
63. each of them appropriate for certain situations e A complete image of your hard drive includes copies of all folders files and programs This backup allows you to restore your computer to its previ ous state after a disk failure A complete image of a drive is sometimes described as a clone e An incremental backup only includes copies of the files that have been installed or have changed since the last backup Incremental backups are faster than complete backups because they don t include the unchanged files that are already part of your backup e A selective backup only includes the important files and programs on your computer This backup is generally faster and takes up less space on the backup drive than a complete backup because it does not include things like temporary files old log files and downloads that you will never use again e A data file only backup can be useful when you expect to restore the backup to another computer that already has the operating system and application programs installed You can also re install the operating system and programs from their CDs or other media If you do choose this option remember to check each program s website for the latest patches and upgrades before you try to use that program e A limited backup includes only one or more specific types of files such as music photos or documents This kind of backup is usually a supple ment to a more complete backup that includes all the ess
64. even an antique 486 CPU so you can often recycle an old junker and use it as a firewall Both the Apache application and the operating system are available as open source software so it ought to be possible to build an extremely low cost Apache firewall If you prefer to use Windows or if you don t want to assemble your own firewall you have several options You can use the Windows version of Apache or you can use a commercial utility such as the ones listed at hitp www thegild com firewall Attacks on a wireless LAN don t all come through the air A wireless network also requires the same kind of firewall protection against attacks from the Internet as an entirely wired network Many wireless access points include configurable firewall features but if yours does not the network should include a firewall program on each computer along with a separate router or a dedicated computer acting as a network firewall Protecting Individual Computers Client firewall programs provide another line of defense against attacks coming from the Internet Some of these attacks come from miscreants who are looking for a way to read your files and other resources that you don t want the entire world to see Others might want to use your computer as a relay point for spam or attempts to break into some other computer halfway around the world in order to make the real source more difficult to identify Still others spread viruses or use really unplea
65. im Trillian Attp www ceruleanstudios com and meebo http www meebo com are available that can exchange messages with people on different services from a single contact list and message window To set up anew IM account with one or more of the major services go to their respective websites e Google Talk http www google com talk e Jabber htip www jabber org e AIM or AOL Instant Messenger hitp www aim com e Yahoo Messenger hitp messenger yahoo com e Windows Live Messenger hitp get live com messenger e Gadu Gadu based in Poland with Polish language screens hitp www gadu gadu pl In house LAN messaging offers several advantages over Internet messag ing services for exchanging messages within a business or a household It s more secure and more private because the messages never leave the LAN And they aren t exposed to spam and other unwanted messages from strangers through the Internet In addition they don t use bandwidth between the LAN and the Internet so they don t interfere with other activities and they don t require a separate account for each user with an IM service although the major IM services all offer free accounts More importantly a local messaging system controls all of your messages within the LAN rather than sending everything to an outside service Messaging Through a LAN Many LAN messaging programs are available all with similar feature sets Some are li
66. in one devices 199 201 200 Amanda Advanced Maryland Automatic Network Disk Archiver 104 American Standard Code for Informa tion Interchange ASCII 10 encryption keys 180 181 182 AM radios 209 214 analog to digital conversion 206 207 209 211 212 antennas 4 80 82 84 85 antivirus programs 245 AOL Instant Messenger AIM 158 234 235 Apache web server 95 156 Apple 21 95 AirPort Extreme 99 99 181 computers 94 iChat 237 ASCII See American Standard Code for Information Interchange ASCII asia 40 Association for Home Appliance Manu facturers AHAM 223 Audacity 208 211 audio clients 211 212 213 devices 213 214 214 controls 51 converters 206 207 209 211 files 203 205 206 214 210 212 214 formats 209 210 210 messaging 237 player programs 210 211 servers 7 8 207 209 212 213 213 Audio Interchange File Format AIFF files 209 210 audiophile music servers 209 automatic printer switches 194 195 automatic updates 185 186 786 Auxiliary input 212 254 INDEX baby monitors 205 backup files 100 104 101 103 104 BackupPC 104 Backup Status and Configuration 103 bands 79 bandwidth 3 4 bar code readers 224 Baseline Security Analyzer 188 188 BBG 3 Belkin 216 BIOS utilities 71 75 BitDefender Online Scanner 245 bits 70 10 11 biz 40 BlackBerry devices 77 bridges 32 Broadcast Wave files 210 brute force programs 153 BSD systems 95
67. intruders and crackers First you can accept the fact that wireless networks are not completely secure and use the built in network security features to slow down would be intruders second you can supplement your wireless router s built in tools with a hardware or software firewall or both to isolate the wireless network but remember that a cracker who can grab and decode encrypted network passwords can often grab firewall passwords too and third you can use additional encryption such as a VPN virtual private network to make the network more secure The security features of the early Wi Fi protocols WEP encryption were not adequate to protect data The WEP protocol was flawed in several ways WEP should be treated more as a Do Not Disturb sign than as a real means of protection The WPA Wi Fi Protected Access and WPA2 standards attempt to fix the shortcomings of WEP but they work only when all of the users of your network have modern cards and drivers Here are some specific security methods e Don t use your access point s default SSID Those defaults are well known to network crackers e Change the SSID to something that doesn t identify your business or your location An intruder who detects something called BigCorpNet and looks around to see BigCorp headquarters across the street will tar get that network The same thing goes for a home network Don t use your family name or the street address or anything else t
68. more when you set up your new connections Reserved Addresses As Chapter 3 explained your LAN communicates with other networks through a router As far as the networks connected to that router are concerned the router is just one more network connection with an IP address Therefore as Figure 4 1 shows a router has two different IP addresses one for its connection to the LAN and the other for the WAN or the Internet The router presents a single address to the Internet that represents all the computers and other devices on your LAN it performs a function called network address translation NAT that converts your public address to the addresses of individual network devices One of the benefits of this system is that you can use the same IP addresses within your LAN as your neighbor across the street or a LAN on the other side of the world and the addresses won t interfere with one another In order to make this system work properly IANA has reserved several blocks of IP address numbers for LANs when a router receives a packet with an address in one of these ranges it does not relay the packet to the Internet If you use these addresses for the devices in your LAN you can be certain that your packets and the commands messages and files that make up those packets won t end up at the reading room of the National Library of Ecuador when you wanted to send them to your assistant across the corridor The reserved IP addresses are
69. neighborhood you will probably see a list of nearby networks in addition to your own access point The control program will also tell you what kind of encryption if any each network is using In the example shown in Figure 13 16 one network RedGoldandGreen is wide open and four others are encrypted two of the encrypted networks use WPA and the two that are listed as security enabled without an encryption type use WEP t Wireless Network Connection Network Tasks Choose a wireless network Refresh network list Click an item in the list below to connect to a y reless network in range or to get more Information x Set up a wireless network Q MASTERMIND for a home or small office if Security enabled wireless network WPA p RedGoldandGreen Related Tasks Unsecured wireless network 4 Learn about wireless Qg Toadhall networking 7 Security enabled wireless network WPA Ze Change the order of Ug mcbright preferred networks i if Security enabled wireless network P Change advanced settings p Bera H f Security enabled wireless network Figure 13 16 Four of the networks in this neighborhood require an encryption key before they will connect Do the math Your access point can reach 150 feet or more in all directions so the signal probably extends beyond your own property lines or the walls of your apartment or office A network device in the building next door or across the street can probabl
70. network The connections inside a combined device don t require external cables As Figure 3 6 shows the area where your net work cables plug into your switches routers modems and so forth is almost always a rat s nest of confusing wiring anything you can do to reduce the number of cables will make things a lot easier dy Figure 3 6 The cables connected to your network controls can often form a confusing mess Hubs Switches and Routers 33 HOW COMPUTER NETWORKS ARE ORGANIZED through a network all the computers connected to that network must use the same set of rules known to network designers as a protocol The rules that control the Internet are called transmission control protocol Internet protocol TCP IP Even if you don t plan to connect your network to the Internet right now you should use TCP IP for at least two reasons First TCP IP is built into the Windows Macintosh and Linux operating systems and most inexpensive networking equipment and second you would waste a lot of time and money finding equipment that works with one of the other older network protocols This chapter offers a relatively simple explanation of the TCP IP protocols and how your network uses them 36 TCP IP Networks Chapter 4 TCP IP is really a suite of protocols The most important are TCP trans mission control protocol which controls the way commands messages and files are broken into packets and reassemble
71. networks because the same data that moves between a computer and a base station by radio can be intercepted by another computer Even if the data is encrypted 78 a dedicated intruder with enough time can steal passwords credit card num bers and other personal information However the latest security tools including WPA encryption and virtual private networks VPNs can go a long way toward making a Wi Fi network secure This chapter describes the types of Wi Fi networks and explains how to add a Wi Fi hotspot to your LAN how to select and use a Wi Fi network interface with your computer and how to keep your Wi Fi network as secure as possible Types of Wi Fi Networks NOTE Chapter 8 Wi Fi networks use the IEEE Institute of Electrical and Electronics Engineers 802 11 family of standards to define the radio frequencies data formats and other technical details that are necessary to establish a wireless LAN Today there are four types of 802 11 networks as shown in Table 8 1 Table 8 1 Wireless Network Standards 802 b 11 Mbps 300 feet 100 meters 24GHz 802 11a 54 Mbps 75 100 feet 23 30 meters 5 2 GHz 802 11g 54 Mbps 300 feet 100 meters 2 4 GHz 802 11n 248 Mbps 750 feet 250 meters 2 4 GHz 5 2 GHz The useful distance that an access point can reach is often considerably less than the promised maximum especially when the path between the access point and a computer s wireless adapter is indoors Walls
72. networks VPN via 173 174 Public Telephone Switched Network PTSN 21 22 PVC pipes 58 Q QuickTime 218 Owest 174 radio Internet 209 214 radio signals 2 4 14 16 20 69 77 79 81 85 160 174 184 radio transmitter receiver 80 81 RADIUS Remote Authentication Dial in User Service 182 183 RCA phone plugs 218 Real Audio and Video 158 210 RealPlayer 208 218 RealVNC 226 229 Registered Jack 70 remote access 226 conferencing 205 237 data entry 224 desktop programs 226 229 227 228 sensors and controls 223 224 232 terminals 23 23 webcams 204 Remote Authentication Dial in User Service RADIUS 182 183 Remote Desktop Connection Client 226 reserved addresses 37 restart options 241 242 RG6 U cables 65 rips 208 RJ 11 telephone plugs cables 64 65 70 70 RJ 45 plugs jacks 66 67 70 70 75 193 Roku 213 root servers 40 Ross John Wiring Home Networks 57 routed VPN traffic 164 routers combination boxes 33 configuring 86 gateway 6 6 32 109 110 installing 59 61 62 64 63 IP addresses 38 location of 50 network to Internet connections 109 115 114 overview of 32 33 rsync 104 Ruska Jimmy 154 Samba operating system 96 Samba Shares folder 148 150 SATA hard drives 97 scanning devices 199 201 200 secondary switches 53 second level domains 38 Secure Shell SSH 104 Secure Sockets Layer SSL 89 164 176 security network See netw
73. newer PC ExpressCards that are gradually replacing PC cards in the latest generation of laptop com puters However built in Wi Fi adapters were already standard features in most laptops by the time PC ExpressCard sockets were introduced in 2004 and 2005 so there s generally no reason to search for a separate adapter On the other hand a PC ExpressCard adapter might be the best way to add Wi Fi to your desktop if there s a PC ExpressCard socket on the computer s case USB Adapters USB Wi Fi adapters are available in two different forms small modules that plug directly into the computer s USB port and stand alone devices that connect to the USB port through a cable The separate units often provide better connections because they have more powerful transmitters and more sensitive receivers but they re considerably less convenient than the small modules especially with a laptop Figure 8 5 shows both a stand alone USB adapter and a plug in USB Wi Fi module The smaller and cheaper plug in USB Wi Fi modules are often entirely adequate to connect your computer to a Wi Fi network unless youre using the computer at the fringe of the access point s coverage If you can detect a strong signal with a plug in module you won t get better performance with a stand alone device However a separate adapter with a more powerful transmitter and a more sensitive receiver might allow you to use a signal that the smaller module won t detect
74. of a network File sharing has many uses You can use it to collaborate with other people on a single document or other file to play music or watch videos stored on another computer and for just about everything else that you can do with your own files In effect every unprotected file stored on any network computer is as easy to use as a file on your own computer For example Figure 1 1 shows a Windows display of disk drives and individual directories on a home network other file sharing methods also exist You can open a file or folder on a remote computer by double clicking an icon or a filename just as you would on your own machine C on Bedroom Bedroom E 8 x File Edit View Favorites Tools Help O Back v X Search Folders gt 5 X 2 Tv Address 2 Bedroom C d Folders x erie Nenion r C c CJ LJ Aire vetwon OBibafcd 539f5d4f Documents Downloads 63 Microsoft Terminal Services and Sett 5 69 Microsoft Windows Network s Local bJj LJ EJ Bedroom Icons Links More Radio NVIDIA F 2G Stations i2 SharedDocs W Printers and Faxes LJ LJ Desktop Desktop Program RECYCLER System WINDOWS 9 Tower Files Volume In 6 Web Client Network E a mj i2 C on Desktop Desktop i2 c on Tower Computer Tower i2 d on Tower Computer Tower nd amlogtxt AUTOEX AVG7QT F F ig Drive D D on Desktop Desktop m fH id e on Tower Computer Tower Beecham boot ini CONFIG IO SY
75. or more updates Microsoft Baseline Security Analyzer Chapter 13 Microsoft s Baseline Security Analyzer is a free tool that scans computers running Windows XP and Windows Vista to identify security threats and vulnerable features and functions You can download it from Attp technet microsoft com en us security cc 184924 aspx You can use the Baseline Security Analyzer to scan your own computer or as network manager you can test other computers connected to yours through your LAN Baseline Security Analyzer provides a quick and easy way to find and fix many common security issues Figure 13 22 shows the result of a Baseline Security Analyzer scan For each item it identifies you can click a link to an explanation What was scanned and instructions for correcting the problem amp Microsoft Baseline Security Analyzer 2 1 Microsoft W Baseline Security Analyzer Windows Scan Results Administrative Vulnerabilities Score Issue Result 9 Local Some user accounts 4 of 7 have blank or simple passwords or could not be anatyzed Account r Result det t tt Password Test LJ Autologon Autologon is configured on this computer Md Guest The Guest account is not disabled on this computer Account What w to correct th Password Some user accounts 4 of 7 have non expiring passwords Expiration What n Result t tt e Incomplete No incomplete software update installations were found Updates What windows
76. or small business network up and running you can use the network to accomplish some things you might not have expected This chapter describes a handful of other useful network applications None of these is reason enough to install a network but if you have come this far you re already using the network for other purposes Consider the network programs and services in this chapter as lagniappe a little extra that might enhance your networking experience 226 Remote Desktop Chapter 16 Remote Desktop programs allow another user with your permission to take control of your computer through a network When a remote control program is active a network manager or service technician can distribute and install new or updated software provide help and remote assistance and view information on other computers Remote Desktop programs are a standard feature in Windows XP Windows Vista and Macintosh Several open source remote desktop programs for Linux and Unix are also available including Virtual Network Computing VNC FreeNX 2X Terminal Server and X Display Manager Control Protocol You can find links to downloads for all of these programs at Attp blog lxpages com 2007 03 13 remote desktop for linux For Mac to Windows remote access try Microsoft s Remote Desktop Connection Client for Mac Attp wwuw microsofl com mac products remote desktop For Windows to Mac use a Windows based VNC client such as RealVNC or TightVNC
77. other devices on the same network The server can be a computer that you also use as a workstation a server for other data files a dedicated server for audio files or a component in a stereo or Other Things You Can Connect to Your Network 207 208 Chapter 15 home theater system Regardless of their physical form most audio servers perform these functions e They convert or rip audio tracks from CDs and other sources to one or more standard file formats e They store sound files on a hard drive e They distribute sound files on demand to one or more players e They distribute audio to the network directly from a CD DVD the Internet or some other digital source Like any other server a music server should have a relatively large hard drive with enough space to hold all the individual music files you want to store on it General purpose computers and stereo component music servers can both perform similar services each type has a different combination of cost ease of use and sound quality General Purpose Computers When you use a standard desktop or tower computer as your music server you can use the same computer to serve other types of data You can use free or inexpensive software such as Windows Media Player RealPlayer Sound Forge Audio Studio Exact Audio Copy or Audacity to create or convert files to your standard storage format and you can increase the server s storage capacity by installing one or more additi
78. point should accept at least twice as many MAC addresses as the number of users on your network today Some access points also include a MAC address exclusion feature that allows the network manager to block one or more MAC addresses from access to the network Physical Security Chapter 13 Intruders don t always use technology to crack into a network Sometimes they use brute force methods For example if a thief steals your laptop computer he can often use the convenience features of the computer s software to connect to the Internet through your network read your email and other confidential files and gain access to other computers connected to the same network Other low tech methods include shoulder surfing where the bad guy watches your screen or your keyboard as you type a login name and password and social engineering in which the intruder convinces you to reveal your password or other information because she has convinced you that she has a legitimate use for it There are some things you can do to protect your computer and the data stored in it e Think like a thief and do whatever might be necessary to make the computer difficult to steal Don t leave your laptop in plain sight in an unattended car or walk away from it in a public location such as a coffee shop airport or library In an office with cubicles or open plan workspaces use a chain and lock to secure the computer to a desk file cabinet or oth
79. programs are often provided as part of the driver software supplied with wireless network interface adapters and laptop computers For example Figure 8 6 shows the Wi Fi control program included in Windows XP and Figure 8 7 shows the Intel program supplied with its mini PCI Wi Fi adapters Both programs display a list of all nearby Wi Fi access points and identify those that are using encrypted data To use either program select the name of the network you want and click the Connect button at the bottom of the program window Other programs use different onscreen layouts but they all operate similarly In some cases one of the programs installed on your computer might be more sensitive to weak signals from access points but that usually doesn t matter all of them detect the strong nearby access points signals that you will use most often t Wireless Network Connection Network Tasks Choose a wireless network fg Refresh network list Click an item in the list below to connect to a wireless network in range or to get more information lt Set up a wireless network Ko for a home or small office i f Security enabled wireless network WPA o Related Tasks Security enabled wireless network W Learn about wireless Q Berg Home networking i ff Security enabled wireless network r Change the order of qq Wilmer preferred networks i t Security enabled wireless network P Change advanced settings p Toa
80. slow down the network s performance but slow performance is not likely to be an issue unless your network carries a lot of traffic You can solve this problem by adding a second access point that uses a different channel and dedicating that access point to one or more printers When you set up the Wi Fi link make sure you connect the printer server to your own access point and not to a network owned by one of your neighbors A Wi Fi printer server offers the following benefits e The printer may be located anywhere within range of your Wi Fi network signal e You don t need a dedicated Ethernet port for the printer server e Ifyou need to move the printer you don t have to rewire the network Built In Printer Servers When you buy a new printer for your network consider one that has a built in network printer server along with the usual USB and or parallel ports The builtin printer server will perform like a printer connected through an external printer server but it s easier to install because you don t have to connect additional cables Printers with built in network interfaces are designed for small businesses and other workgroups that often produce a greater number of printed pages than a typical home network or a single user They re often a bit more expen sive than the combination of a low end stand alone printer and a separate printer server device because they re generally more durable printers with more and better fea
81. store chains have been traced to inadequate network protection Maintaining control of your network and keeping it secure is essential Wi Fi Security on page 89 includes a list of specific actions you can use to keep intruders out of your wireless network The security tools in the Wi Fi specifications aren t perfect but they re better than nothing Even if you choose not to use them it s essential to understand what they are and how they work if only to turn them off Network Name Every wireless network has a name In a network with just one access point the name is the basic service set ID BSSID When the network has more than one access point the name becomes the extended service set ID ESSID but your computer s control program displays both types in the same list The generic designation for all network names is the service set ID SSID which is the term you will see most often in wireless access point and client configuration utility programs When you configure the access points for a network you must specify the SSID for that network Every access point and network client in a network must use the same SSID When a network client detects two or more access points with the same SSID it assumes that they are all part of the same net work even if the access points are operating on different radio channels and the client associates with the access point that provides the strongest or cleanest signal If that si
82. the added information instructed it to do By the time a message travels from a laptop computer on a wireless network through an office network and a gateway to the Internet and onward to a distant computer connected to another local network a dozen or more information attachments might be added and removed before the recipient reads the original text A package of data that includes address and control information ahead of the bits that NOTE contain the content of the message followed by an error checking sequence is called a frame Both wired and wireless networks divide the data stream into frames that contain various forms of handshaking information along with the original data The network deals with packets and frames at different places during the process of transmitting data Fortunately this all happens automatically so you as a network user don t have to worry about adding or removing them by hand Error Checking In a perfect transmission channel the signal that goes in at one end would be absolutely identical to the one that comes out at the other end But in the real world there s almost always some kind of noise along the line that can interfere with the original signal Noise is defined as anything that interrupts or is added to the original signal it could be caused by a lightning strike interference from another communications channel devices not working correctly or dirt on an electrical contact someplace in
83. the services you need for a file server operating system FreeNAS is designed for remote configuration and operation and it s relatively easy to set up and use FreeNAS Backup Restore Factory Defaults SCSI Target UPnP Dynamic ONS saMe Access Users and Groups Active Directory UWAP Status System Process Interfaces webGUI Configuration FreeNAS The Free NAS server System informaton Mame eenas local Version 0 6863 revison 2011 buit on Thu Mar 13 19 20 49 CET 2008 OS Version FreetsO 6 2 RELEASE911 revison 199506 Platform 1886 bvecd on AMD Athion tm Processex running at 1008 MHz Date Wed Apr 23 20 43 12 UTC 2008 Uptime ore Last config change Wed Aor 23 20 40 26 UTC 2008 Memory usage ed S HE Load averages 0 00 0 00 0 00 show process information Desk space usage No disk configured freenas loca Figure 9 4 FreeNAS is a simple version of Unix designed for use as a file server USB Device Servers To add one or more stand alone USB disk drives to your network as file servers consider using a USB device server such as the Lantronix UBox 4100 shown in Figure 9 5 The server connects directly to the network through an Ethernet cable and each disk drive or other USB device connected to the server appears as a local device on every computer connected to the network Similar devices are also made by Silex Technology including a wireless USB device server that connects to the network through
84. the Gnome and KDE environments used by many Linux and Unix distributions File Sharing in Windows XP Chapter 12 Windows XP uses a set of programs called Simple File Sharing to exchange files among computers on a network In XP Home Edition Simple File Sharing is always on in XP Professional file sharing is normally turned on but you can turn it on or off To turn Simple File Sharing on or off in XP Professional follow these steps From the Windows Desktop open My Computer 2 Select the Tools menu and choose Folder Options 3 In the Folder Options window click the View tab to open the window shown in Figure 12 1 Folder Options x General View File Types Offine Files Folder wews You can apply the view such as Details or Tiles that you are using for this folder to all folders PH Apply to All Folders Reset All Folders Advanced settings O Hide extensions for known file types O Hide protected operating system files Recommended O Launch folder windows m a separate process 3 Managing pairs of Web pages and folders Show and manage the pair as a single file Show both parts and manage them individually O Show both parts but manage as a single file E Remember each folder s vew settings O Restore previous folder windows at logon Show Control Panel in My Computer El Show encrypted or compressed NTFS files in color E Show pop up description for folder and desktop items BEER file sharing Recommended
85. the network to connect them e Aset of communication channels that carry something speech TV shows computer data between or among nodes e A set of rules that controls network traffic on a highway the rules might specify that vehicles drive on the right and pass on the left and every car and truck must display a license plate to identify it in a tele phone network the rules define the form and use of unique numbers called telephone numbers to identify each node and establish con nections between them To assure that a network operates properly every node and every channel must follow the rules for that particular network Next every network has a maximum carrying capacity For example a four lane Interstate highway can safely carry more cars and trucks at higher speed than a two lane country road In a communications network the capacity of a network connection is the amount of information it can carry also known as its bandwidth Both a telephone call and an FM radio station use audio channels but the same voice sounds better on the FM station because the FM channel has a greater bandwidth that allows more of the original information in this case higher audio frequencies to reach your ear In a data network the speed of a network is usually shown in millions of bits or megabits per second Mbps And finally every node on a network has a name This name might be the same as the name of the person who uses that no
86. the use of a DHCP server or manual settings for IP address and DNS 7 Click the Advanced tab to open the dialog shown in Figure 13 15 If your network is not already protected by a firewall select the Internet Con nection Firewall option This will protect the wireless client from attacks coming through the Internet 4 VPN to Internet Properties 2 x General Options Security Networking Advanced r Internet Connection Firewall v Protect my computer and network by limiting or preventing access to this computer from the Internet Learn more about Internet Connection Firewall r Internet Connection Sharing Allow other network users to connect through this computer s Internet connection Establish a dial up connection whenever a computer on my network attempts ta access the Internet Allow other network users to control or disable the shared Internet connection Learn more about Internet Connection Sharing If you re not sure how to set these properties use the Network Setup Wizard instead OK Cancel Figure 13 15 The Advanced tab controls the use of a firewall on the VPN The Options and Security tabs in the VPN to Internet Properties window control connection options that normally don t change from the default settings Network managers who want to change the security settings should instruct their users on how to configure these options to comply with the network
87. to peer messaging 234 PF Packet Filter 159 Philips 213 picture elements 10 219 picturephones 237 Pidgin 234 pigtails 85 ping command 36 45 43 44 pipsec 173 pixels 10 219 Plain Old Telephone Service POTS 21 22 PlayStation 220 221 plugin modules 83 84 84 plugs 66 67 70 70 75 193 218 242 plywood sheets 59 66 point to point networks 19 20 20 51 52 52 Point to Point Tunneling Protocol PPTP 162 163 164 172 POP3 incoming mail protocol 158 portable drives 3 port assignments port numbers 157 158 158 INDEX 261 262 INDEX ports Ethernet 4 70 74 71 85 97 193 201 216 FireWire 4 21 205 211 infrared 21 input output 4 IrDA 20 21 21 overview of 28 parallel 4 16 192 792 194 TCP service 158 USB 4 16 21 70 73 99 192 194 195 201 205 211 212 216 Port Scan Attack Detector 159 POTS Plain Old Telephone Service 21 22 power converters 61 Power LED indicator lights 240 powerstrips 61 61 PPTP Point to Point Tunneling Protocol 162 163 164 172 pre assembled cables 56 pre shared key PSK mode 182 183 printers connecting to network 191 201 192 194 199 200 servers 7 25 25 193 197 sharing 7 143 196 196 199 198 199 switches 194 195 private folders 5 protocols 35 36 115 PSK pre shared key mode 182 183 PTSN Public Telephone Switched Network 21 22 Public DNS servers 41 public folders 5 139 141 public
88. to the end of the list of items select Internet Protocol TCP IP and click the Properties button The Properties window shown in Figure 11 9 will open Internet Protocol TCP IP Propertics 2 x 198 137 231 1 SE Figure 11 9 The Internet Protocol Properties window controls your network and Internet settings Connecting Your Computer to a Network 123 124 To use this computer with a DHCP server select the Obtain an IP address automatically radio button To assign and use a static IP address select the Use the following IP address option and type the numbers of the IP address subnet mask and default gateway To use the DNS server specified by the DHCP server select the Obtain DNS server address automatically radio button To specify one or more DNS servers on this computer select the Use the following DNS server addresses radio button and type the addresses for the preferred and alternate DNS server Connecting Your Macintosh Computer to a Network Chapter 11 To connect a Macintosh computer running OS X to your network follow these steps 1 If it s not already in place install an Ethernet cable between the computer and the network s hub switch or router From the Macintosh desktop click the Apple icon at the extreme left side of the Menu Bar to open the Apple Menu The System Preferences window shown in Figure 11 10 will appear eoc System Preferences gt Show All Q Personal
89. to turn on the builtin filters in your firewall and modem install all the latest security patches to your software and network hardware and work closely with your Internet service provider at the first sign that your network is under attack Most ISPs have more sophisticated monitoring and filtering resources that can help them identify and interrupt an attack In the United States DoS attacks are a violation of federal law so it s appropriate to ask your local FBI field office for assistance in finding and prosecuting the source of an attack Conclusion As manager of a home or small business network maintaining its safety and security is one of your primary responsibilities The methods outlined in this chapter combined with some commonsense attention will allow you and your users to concentrate on the business and recreational use of your computer your network and the Internet Network Security 189 PRINTERS AND OTHER DEVICES ON YOUR NETWORK to a small business or a household full of computer users is the convenience of sharing one or more printers among all the network s users Rather than carrying a copy of each file to the computer connected to the printer on a disk ora flash drive you can simply click the Print command on your own computer and let the network send it to the printer automatically Even a very small network might include more than one printer For example you might use a black and white laser p
90. use the Restart option that can leave some settings at the same values rather than resetting them to the default startup configuration You should turn off the computer completely count to ten and then turn it back on Troubleshooting 241 242 Chapter 17 If the problem continues after you restart the computer try restarting the modem Wi Fi access point or network router If a device doesn t have an on off switch disconnect the power cable wait a few seconds and plug it back in After you restart each device check to find out if the problem still exists If the problem still occurs move on to the next device Check the Plugs and Cables If a single computer can t connect to the network confirm that the physical cables providing those connections are not unplugged Be sure to check both ends of each cable If the whole network can t find the Internet check the cables connected to the modem If possible examine the cable itself to make sure it hasn t been cut someplace in the middle Almost all routers switches modems and network adapters have LED indicators that light when they detect a live connection If one or more of these LEDs has gone dark check the connection Most data plugs and sockets maintain solid connections but it s possible that a plug might have come loose without separating itself from the socket or a wire inside the plug might have a bad contact If you suspect a loose connection try wiggling the cabl
91. use the printer or connect to the Internet at the same time Are they connected to the network by Ethernet cables or Wi Fi Does the problem happen at the same time every day If you re lucky defining the problem can tell you enough to fix it For example if the Power LED indicator light on your modem is off that s a good indication that the power cable is unplugged either at the wall outlet or on the modem itself If everybody has trouble connecting to the Internet during a rainstorm maybe water is leaking into the telephone cable that carries your Internet connection from the utility pole to your house that NOTE happened to me the repair guy told me that the cable had been there since about 1927 More often your list of symptoms will be a starting point that you can use to search for more information As you analyze the problem ask yourself these questions What caused the problem Did it occur when you or another user ran a specific program or tried to connect Does the problem seem to be related to some other action If you try the same action again does the same problem occur Did it first appear when you turned on a computer What has changed Have you installed new hardware on the network or loaded new software on the server or another computer Did you recently update the router s firmware Have you made any other change to the network or another connected computer even if the change seems unrelated to the problem
92. using a home entertain ment network see Chapter 15 Video Cameras and Home Security Devices A stand alone video camera often with a built in microphone connected to your home network can have several uses You can place a camera at the front door to identify visitors or use one in a nursery or playroom to keep an eye on your children from computers in other parts of the house Other devices can use special sensors to detect smoke and fires unlocked or open doors and windows broken glass or flooding and other problems and send alerts to the homeowner on a local computer or to a home protection service through the Internet Combined with a wireless network link the same kind of security moni toring can extend to a detached garage shed or other separate buildings even if the house s wired network does not reach those locations Chapter 15 explains how to connect and use cameras and other security devices to your network Home Automation Home automation systems usually use separate wiring from a household data network but sometimes they re closely integrated Home automation can be as simple as turning on outside lights after the sun goes down or as com plex as opening and closing drapes monitoring and adjusting heating and air conditioning operating a lawn sprinkler or filling the dog s water dish You can also expect the next generation of smart kitchen and laundry appliances to include network connections that wil
93. video it would seem that there isn t a lot of difference between a TV screen and a computer monitor But they use different methods to accomplish the same objective and these methods create problems when you try to move from one to the other The difficulty arises because of the way computer monitors and TV screens break an image into scan lines and pixels For the purpose of this explanation we can think about a still picture but the same problems can also occur in a moving image In North America an analog TV shows images as a sequence of 535 scan lines from left to right across the face of the screen when the TV reaches the end of one scan line it moves down to the next one In digital TV the screen is divided into a large number of dots called picture elements or pixels The method used by the TV to light up segments of scan lines or pixels is different on picture tubes and flat panels but the number of scan lines or pixels is specified by industry standards The size of the screen doesn t matter the number of scan lines or pixels on a screen is always the same there are several different standards for flat panels depending on size and cost but the number of pixels is constant for each standard Computer monitors also use pixels but the number of pixels in an image is different depending on screen resolution When you change your monitor s resolution from say 800 x 600 pixels to 1280 x 1024 pixels the computer adjusts the number
94. web resource at that address uses as a leading part of the address followed by a colon and two forward slashes such as hitp host sample com The http part stands for HyperText Transfer Protocol the protocol that defines most websites If you want to reach a different service at the same destination such as a file transfer server a telnet host or an Internet Relay Chat server you might instead use tp host sample com telnet host sample com ox irc host sample com respectively When an address does not include the protocol type and the two forward slashes your web browser will assume it s an http address Some top level domains that use country codes have other structures that differ from one country to another Domain names that have a us for United States top level domain sometimes use subdomains also called second level domains that identify the state and city where the owner is located such as example sf ca us which would be in San Francisco California In Canada and other countries the domain name comes right before the country code such as the Canadian Broadcasting Corporation s cbc ca whereas other countries use generic identifiers along with the geographic domain such as bbc co uk for the British Broadcasting Corporation the co stands for commercial and the wk for the United Kingdom How Computer Networks Are Organized 39 40 NOTE Chapter 4 Just because a domain name address has a country code t
95. who tries it is convinced that the second screen makes them much more productive Because you can keep two or more windows open at the same time without the need to bring one of them to the top you can work more efficiently just for starters you can drag text figures or data from one document or program to another view large documents and graphics without scrolling from one end of a document to the other and keep a web browser or video surveillance window open on one screen while you work on the other If you re writing code or working on a web page you can save your work and immediately see what your latest changes look like in an application window or a browser And in many Windows programs you can drag one or more toolbars away from the main program window to the second screen in order to make more of your work visible Two or three or more monitor screens on your desk will change the way you work with your computer Figure 16 4 shows a desktop extended across two laptop computer screens Figure 16 4 Windows can show a single large window extended onto two or more screens If you have an old monitor in the back of a closet try adding it to a computer Even if the monitor isn t the same size as your main monitor it will still work and be an improvement over a single screen The easiest way to add another monitor to your system doesn t require MaxiVista or any other special software simply plug the monitor into a spare VGA
96. you will probably solve the problem without developing or enlarging an ulcer Over time you will recognize particular symptoms and know how to home in on the most effective diagnostic tools and techniques If you can t find the problem after searching for an hour walk away for a few minutes Make yourself a sandwich have a cup of coffee or a glass of lemonade or go for a short walk The network will still be there when you get back and you ll feel better about it Approaching the problem with a fresh mind can often be the most effective possible way to solve it Troubleshooting 251 INDEX Page numbers in italics refer to figures tables and listings Numbers 2X Terminal Server 226 3COM 164 3G broadband networks 174 10 100 indicator lights 75 10Base T networks 14 15 10 Mbps operations 29 100Base T networks 14 15 100 Mbps operations 29 1000Base T networks 14 A Access Microsoft 95 access points Wi Fi 53 55 62 80 81 81 85 87 90 99 111 113 174 AC power 17 48 49 50 51 60 61 67 75 242 ACT indicator lights 75 addresses and names 36 41 38 48 See also Internet Protocol IP addresses ad hoc networks 20 administrators 152 Advanced Maryland Automatic Network Disk Archiver Amanda 104 AHAM Association for Home Appli ance Manufacturers 223 AIFF Audio Interchange File Format files 209 210 AIM AOL Instant Messenger 158 234 235 AirPort Extreme 99 99 181 all
97. 0 can all connect to your home network through either a wired Ethernet port or a wireless link to support multiplayer games with one or more additional consoles on the same LAN or through the Internet they could also connect to a business network but your employer probably would not approve Connecting a PlayStation To connect through a wireless link use the PlayStation s built in Wi Fi inter face To connect a Sony PlayStation to your network through an Ethernet cable run an Ethernet cable from the game console either directly to an Ethernet hub or to a router To configure the network connection follow these steps 1 Turn off or disconnect power from your network hub modem Wi Fi base station and other network equipment wait two minutes and then turn everything back on again 2 Ifthe PlayStation console and attached display are not already turned on turn them on now 3 Confirm the PlayStation s connection to the Internet is active From the XMB home menu select Settings gt Network Settings gt Internet Connection gt Enabled 4 Select Internet Connection Settings and press the button The PlayStation will ask Do you want to continue 5 Select Yes The PlayStation will ask you to select a connection method 10 Select Wired Connection and press the button The Internet Connec tion Settings screen will appear Select Easy and press the button The PlayStation will scan your con nection and
98. 0492 scale fa 72 246 51 15 d static feedroor com t_assets 2008 1002 2 1934672926169 147 2e4946 2 f2308799 00603 jog DESKTOP A SrcPortel DstPort 7158 Len 0 Seq 1113000487 Ack 1609178691 Win S840 scale fa 72 246 51 15 TCP Flags SPort 7158 DstPorts HTTP 80 Len 72 246 51 15 A jate feedroom DESKTOP e Control Ethernet Etype Internet IP IPv4 no transf Ipv4 Next Protocol TCP Packet ID 2539 Total orm UA CP Tcp Flags PA SrcPort 7156 DstPort HTTP 80 U x86 If i Modified Http Request GET static feedroom com t assets 2 Since Thu 02 Oct 2 008 17 30 04 GMT le Figure 17 3 Microsoft Network Monitor displays detailed information about network data Untitled Wireshark 44 11 793820 Who has 192 168 1 1 Tell 192 168 1 45 11 794139 r bf 192 168 1 1 is at 00 20 78 30 170 149 173 130 192 168 1 100 170 149 173 130 170 149 173 130 170 149 173 130 192 168 1 100 54 12 338395 170 149 173 130 192 168 1 100 55 12 340788 170 149 173 130 192 168 1 100 Source port http 80 Destination port 6991 6991 Sequence number 26459 relative sequence number Next sequence number 27839 relative sequence number Acknowledgement number 1381 relative ack number Header length 20 bytes Flags 0x10 ACK Window size 64860 Checksum Ox4fdd correct 68 6f 77 3a 20 50 69 63 how Pic tures of 20 74 68 65 20 44 61 79 the Day class 22 63 61 6c 6c 6f 75 74 callo
99. 10 Mbps NOTE To install an internal Ethernet adapter follow these steps Turn off the computer and unplug the power cable Remove the cover from the computer s case Find an empty expansion slot on the motherboard Ie UPS ir un Remove the metal bracket attached to the computer s frame directly behind the empty slot Save the screw you ll need it to secure the adapter card 5 Line up the bottom of the adapter card with the slots in the expansion socket and push it into place 6 Use the screw you saved from the old bracket to secure the adapter card 7 While the computer case is off clean out the accumulated dust and make sure none of the connectors attached to the motherboard and the drives have come loose 8 Replace the cover and plug in the power cable 9 Plug a network cable into the new Ethernet jack in the back of the computer 10 Turn on the computer If the operating system does not automatically detect the new network connection load the driver software USB Adapters A computer that has built in USB ports but no Ethernet ports can use an external USB network interface as an alternative to an internal expansion card but the data transfer speed might not be as fast USB adapters are widely available but very few computers need them By the time USB ports became common features on computers onboard Ethernet ports were also standard equipment Network Adapters for Laptops An old laptop without a
100. 208 209 211 MAC addresses 43 91 184 authentication 184 185 Macintosh OS X 35 43 44 backup files 100 103 104 104 computer to network connections 117 124 124 127 125 126 127 file servers 94 95 96 99 99 215 file sharing 131 134 135 143 147 144 146 IP addresses 112 772 118 network adapters 73 74 network security 184 185 network to Internet connections 115 OpenVPN for 173 remote desktop programs 226 229 227 228 troubleshooting info 247 wireless control programs 87 Mac to Windows remote access 226 mail servers 24 M Audio 211 MaxiVista 229 232 Mbps megabits per second 3 McIntosh MS750 209 Media Center Extender 208 media sharing 143 meebo 234 megabits per second Mbps 3 mesh topologies 28 messages sending 11 13 14 message servers 234 messaging 233 237 microphones 8 204 205 Microsoft Baseline Security Analyzer 188 188 Knowledge Base 247 MSN Messenger 158 Protocol Analyzers 248 250 Resource Kit 163 SOL 95 SyncToy 232 TechNet articles 163 Windows See Windows Xbox 360 220 222 microsoft com 44 microwave radio links 3 mini PCI cards 81 82 82 84 87 MoCA Multimedia over Coax Alliance 17 modems 6 cable 110 combination boxes 33 configuring 86 dial up 109 DSL 62 110 high speed 109 installing 59 61 62 64 63 location of 50 network to Internet connections 108 115 null 19 19 PTSN 21 22 telephone line connections and 21 23 m
101. 78 Built in Ethernet f TCP IP DNS WINS AppleTalk 802 1X Proxies Ethernet Configure IPv4 Using DHCP IPv4 Address 192 168 1 103 Renew DHCP Lease Subnet Mask 255 255 255 0 DHCP Client ID If required Router 192 168 1 1 Configure IPv6 Automatically Router IPv6 Address Prefix Length A Cancel OK Figure 10 3 In OS X choose the Using DHCP option to obtain an IP address from a server In this example the important settings are DHCP Server and Starting IP Address When the DHCP server is enabled the server provides IP addresses for the entire network When the server is disabled each computer and net work node uses a static address that you must set on that computer or node http 192 168 1 1 DHCP htm Windows Internet Ex CI Je http 192 168 1 1 DHCP htm File Edit View Favorites Tools Help Gose c e amp http 192 x DHCP Acti You can configure the router to act as a DHCP Dynamic Host Configuration Protocol server for your network Consult the user guide for instructions on how to setup your PCs to work with this feature Enable c Disable 192 168 1 100 50 0 minutes 0 means two day DHCP Clients Table Apply Cancel Internet 100 v Figure 10 4 The DHCP server sets the IP addresses for the entire network NOTE The Starting IP Address setting specifies the lowest IP address number that the server will assign to a client device
102. 8 129 local area 122 123 123 Macintosh OS X 117 124 124 127 125 126 127 overview of 117 118 Unix 117 127 127 129 128 129 Windows 117 118 118 124 119 120 121 122 123 Wireless Network Connections profile 122 network to Internet 107 115 108 111 112 other devices audio music files 203 205 206 214 210 212 214 baby monitors 205 bar code readers 224 game consoles 220 222 home appliances 8 222 228 home entertainment systems 7 8 48 49 203 206 Internet radios 209 214 live conversations 205 233 237 microphones 8 204 205 remote conferencing 205 237 remote data entry 224 remote sensors and controls 223 224 stereos 206 212 surveillance monitors 205 traffic monitors 204 video files 203 205 215 220 webcams cameras 8 204 204 205 237 types ad hoc networks 20 clients and servers 23 25 25 common elements of 9 14 DTE DCE equipment for 18 19 error checking 9 13 Ethernet 14 16 15 FireWire ports 4 21 205 211 infrared networks 20 21 21 Plain Old Telephone Service POTS 21 22 point to point 19 20 20 51 52 52 powerline networks 16 17 Public Telephone Switched Network PTSN 21 22 22 remote terminals 23 23 servers 23 25 26 telephone line connections 21 22 22 Wi Fi 16 See also Wi Fi wireless fidelity wired networks 16 wireless programs 87 87 89 88 Network Connections window 116 118 119 122 169 170 173 190 networked Internet radios 214
103. ASA Cataloguing Rules mht Properties i General Security Dotais Otyect name C Audo ArchvesilASA Cataloguing Rules mht Permissions for IASA Cataloguing Rule Ea Group or user names Security eS Object name C Aude Archives ASA Cataloguing Rules mht R Account Unknown S 1 5 21 1614895754 1844237615 83952 St Administrators Tower Administrators t Users TowerlUsers CETTE ia SYSTEM R Account Unknown S 1 5 21 1614805754 1844237615 83052 it Administrators Towor Administrators amp Users TowerlUsers Group or user names To change permissions cick Edit Permissions for Everyone Full control Modity Read amp execute Read Permissions for Everyone Write Full control Special permissions Modity Read amp execute For special permissions or advanced settings Read chick Advanced write Figure 12 10 The Security tab con Figure 12 11 Use the Permissions dialog trols file sharing permissions for indi to change permission settings for one or vidual files more users The lower part of the dialog includes Allow and Deny checkboxes for each of six different options To change a setting click to add or remove a checkmark from the appropriate box The options are Full control A user with full control can read and write data files run program files edit or delete files and change a file s permissions Modify A user with Modify permissions can run a program file and read write or delete a data file
104. Boxes As part of your floor plan you chose a location in each room for a network outlet In places where you decide to use surface boxes you can attach the outlet block to the baseboard with double sided adhesive or wood screws For wall plates you must cut a hole in the wall and use a mounting bracket like the one shown in Figure 6 1 to attach the plate to the wall If there s an 56 electrical outlet on the same wall measure the distance from the bottom of the plate to the floor and mount the data plate at exactly the same height Remember to keep data outlets at least a foot away from the nearest electrical outlet When you tighten the screws on the front of the mounting bracket the wings inside the wall will turn and hold the bracket in place Figure 6 1 Use a mounting bracket to attach data outlet wall plates to a wall If you want to install a single combined wall outlet plate for data telephone wiring and video use a modular plate with snap in connectors For a single purpose outlet use either a snap in connector or a plate with the data outlet permanently attached Ethernet Cable NOTE Chapter 6 All Ethernet cables have four color coded pairs of wires twisted together green with green and white brown with brown and white and so forth Ethernet cables and connectors are identified as Category 5 CAT5 enhanced Category 5 CAT5e or Category 6 CAT6 depending on the amount of data that can pass through a cab
105. Guide which is available at http www microsoft com windows products winfamily windowshomeserver support mspx o Windows Home Server Console As DesxToe ior 6 tet bated up Ae THINCPAD 200M J Ntbededup uy romer Wx dodedup Figure 9 1 The Windows Home Server Console offers many control options on a single screen In order to use shared files stored on a Windows Home Server from other computers in your network you must install the Connector program supplied with WHS onto each client machine Without this software the clients won t find the shared files Connector is only available for Windows XP and Vista so Home Server is less useful with Macintosh and Linux Unix clients Using a Server for File Storage Chapter 9 The easiest way to set up a file server is simply to connect a computer to the network and designate it as a server Create one or more folders for shared files and set the Permissions or Network Sharing characteristics to share files in the directories or folders with network users If you re storing photos music or video files on the server create one or more separate folders for those files and set the permissions to read only allowing network users to open the files but not to change them Figure 9 2 shows the Sharing tab that controls these settings in Windows XP For more information about sharing files see Chapter 12 Photos Properties x General Sharing Customize r Local shari
106. Media Center hitp xmbc org is an excellent choice for managing and sharing media files Remember to configure the folder or drive that contains the server s music files as a shared resource that is accessible to other computers and devices on the same network Special Purpose Music Servers Audiophile music servers store music and other audio files on a hard drive and they generally perform two kinds of playback They connect directly to a stereo or home theater system as a local program source and they also connect to an Ethernet or Wi Fi network to serve music files to computers and audio devices in other rooms Music servers sold as audiophile equipment generally contain high quality internal parts and often front panel text displays that provide information about the music track currently playing Many of them such as the McIntosh MS750 are also very expensive Most include their own CD drives for ripping copies to the internal hard drive and analog inputs with excellent analog to digital converters for making digital copies of LPs and other analog source material A music server is an expensive alternative to a computer with a very good internal or external audio interface card or adapter but in a serious audio phile sound system such a server has its place a 3 500 music server might make sense as part of a system that includes a 3 000 amplifier and a pair of 7 500 speakers But the rest of us can accomplish the same thin
107. N MEConnect To 2 e Sample Call Enter details for the phone number that you want to dial Countryiregon United States 1 x Area code 206 User name MsN imi Phone number 555 8562 Password fre change the saved password cick here Connect using U S Robotics 56K Faxmodem Win 7 Save this user name and password for the following users Meonly C Anyone who uses this computer o e Figure 2 10 The Connect To dialog in Dia xj HyperTerminal includes space for an area mie ts code and telephone number da cm Lose Figure 2 9 The Connect dialog in Windows specifies the telephone number that a modem will call and the login and password that the computer will send after the connection goes through Remote Terminals Today most networks connect two or more computers but it s also possible to use your computer as a remote terminal a keyboard and screen to operate another computer that might be located in the next room or halfway around the world Computers using terminal emulator programs send commands from your computer s keyboard to a distant system and they display data from the distant computer on your computer s screen You can connect to another computer as a remote terminal through a LAN through a dial up telephone line or through the Internet For example Figure 2 11 shows the login sequence from a remote terminal program connected to The Well a text
108. N to the Internet you add a router as a node on the LAN This kind of router is sometimes called a gateway router because packets from your LAN must pass through it on their way to the Internet and of course packets from the Internet also pass through the router on their way to your LAN The most common gateway routers are specifically designed to supply the right kind of signaling and address conversion required by DSL or cable TV connections Combination Boxes In relatively small networks the functions of two or more network control devices are often combined into a single box For example a router that con nects the network to the Internet could also include a built in switch that connects several nodes or a DSL modem might be matched with a gateway router Many other combinations are also widely available If you can find one that meets your network s requirements a combined package is almost always a better choice than two or more separate pieces A single unit is almost always less costly than separate components because the case and the power supply account for a major portion of the total price and it s often easier to configure the network when one device handles several activities Using a single device that combines two or more activities offers another advantage that might not be obvious until you have been using your network for a while and you either need to troubleshoot a problem or you want to add more devices to the
109. NETWORK KNOW HOW AN ESSENTIAL GUIDE FOR THE ACCIDENTAL ADMIN TD MM NN ann no starch press www allitebooks com NETWORK KNOW HOW www allitebooks com We are in great haste to construct a magnetic telegraph from Maine to Texas but Maine and Texas it may be have nothing important to communicate Henry David Thoreau Walden www allitebooks com NETWORK KNOW HOW An E ntial Guide for the Accidental Admin by John Ross no starch press San Francisco www allitebooks com NETWORK KNOW HOW Copyright 2009 by John Ross All rights reserved No part of this work may be reproduced or transmitted in any form or by any means electronic or mechanical including photocopying recording or by any information storage or retrieval system without the prior written permission of the copyright owner and the publisher 1312 11 10 09 123456789 ISBN 10 1 59327 191 3 ISBN 13 978 1 59327 191 6 Publisher William Pollock Production Editor Kathleen Mish Cover and Interior Design Octopod Studios Developmental Editor Tyler Ortman Technical Reviewer Mike Kershaw Copyeditors Eric Newman and LeeAnn Pickrell Compositor Riley Hoffman Proofreader Rachel Kai Indexer Sarah Schott For information on book distributors or translations please contact No Starch Press Inc directly No Starch Press Inc 555 De Haro Street Suite 250 San Francisco CA 94107 phone 415 863 9900 fax 415 863 9950 i
110. Network Problem Solver Windows Internet Explorer Js xJ Je http winhlp com wxnet htm uox loc ogle 2 File Edit View Favorites Tools Help cese c Jota sa E vy 4 Windows Network Pro f2v Hy mv ov Ov Ov E Step 1 Fill in the form E The problem definition form How to use it read this carefully You have to fill in the form because otherwise this page is hardly useful Make a d sion and plan 5 minutes The reward will be a very high likelihood of getting your particular problem perfectly solved If you do not fill in the form you will probably not find the solution Please go through the form and click on the checkbox or radio button on the left side next to each best choice The questionnaire expects you to answer as If you were sitting at the computer on which the problem shows up Take a little time and try to be precise Its worth it After each change you make different chapters in the results section below the form are opened shown with full text or closed only the heading is shown Scroll down to see them all Once this page is loaded there is no further Internet data exchange All processing is done only on your computer Fundamentals 1 F Select your computer s symptoms below Network adapter not visible or connection not visible in Network Connections or Device Manager Or if you try to assign a fixed IP address to a new adapter you may get the error message The IP address XXX XXX
111. Network and Sharing Center A a TOWER Local This computer Internet Wis Local Private network Access Local and Internet Connection Local Area Connection Sharing and Discovery Network discovery On File sharing On Public folder sharing On When Public folder sharing is on people on the network can access filles in the Public folder What the Public folder Turn on sharing so anyone with network access can open files Turn on sharing so anyone with network access can open change and create files Turn off sharing people logged on to this computer can still access this folder Printer sharing ot Password protected sharing Off Aneta chseinn ou Figure 12 5 The Network and Sharing Center controls the access level for the Public folder Regardless of the network access settings others using the local computer can always open and edit files in the Public folder Sharing through the Public folder is a good choice when you want to keep all your shared files in one place separated from the files and folders that you want to keep private The Public folder is also an easy way to share files with everybody on the network without needing to set specific per missions for individual users To open the Public folder select the Start menu and choose Documents gt Documents Then select Public from the Favorite Links list in the left panel of the Documents window If the left panel is not visible select
112. OTE Many Wi Fi hotspots that require a password display a web based login screen before they connect you to the first website you try to view These hotspots won t connect to any other Internet service such as email or instant messaging until you log in through a web browser Hybrid Wired Wireless Networks Most home and business Wi Fi networks include at least one computer connected to the network s router through an Ethernet cable rather than via a wireless link The wired connections are often in the same room as the router and modem where there s little or no advantage to using wireless In many networks it might be convenient to run a cable to one or more adjacent rooms but use Wi Fi for computers in more isolated locations Other networks limit Wi Fi connections to laptops smartphones and other portable or handheld devices All the permanent systems use Ethernet cables because they re faster and more secure Wi Fi Security Wireless networks are a trade off between security and convenience The obvious benefits of a wireless network connection fast and easy access to the network from a portable computer or an isolated location come at a cost For most users the convenience of wireless operation outweighs the possible security threats But just as you lock the doors of your car when you park it on the street you should take similar steps to protect your network and your data The simple truth is that someone who wants to
113. Organize from the taskbar directly under the menu bar and then select Layout gt Navigation Pane Figure 12 6 shows the Public folder Gow b Public File Edit View Tools Help Name Date modified Type H Favorites Public Desktop Public Public Public Music Documents Downloads i Public Pictures Public Videos Recorded TV desktop ini i Computer Figure 12 6 Windows Vista s Public folder contains subfolders for different categories of shared files To add a folder or file to the Public folder either move or copy the file or folder into the Public folder or into one of its subfolders The preset subfolders are intended for common file types such as documents music photos and videos you can add new categories or remove the existing ones to meet your own needs and preferences You can also place shortcuts to local files and web pages in the Public folder If you place a copy of your Favorites folder drive letter gt Users username V avorites in the Public Favorites folder you can share your Internet Explorer Favorites list with other network users To open or view a file or folder in a Public folder from another com puter on the same network use that computer s network browser and open the drive letter gt Users Public folder for the target computer Sharing from Any Folder The alternative to the Public folder is to treat each shared file or folder separately Outside of the Public folder you c
114. Pv6 Automatically HE Router IPv6 Address Prefix Length Cancel OK Figure 11 13 Use the Configure IPv4 drop down menu to enable or disable DHCP on this computer Select the option you want to use to assign IP addresses on this com puter Select Using DHCP to obtain an address from the network s DHCP server or select Manually to assign a fixed address If you select the Manually option enter the numeric IP address the sub net mask and the gateway router address in the appropriate fields and click DNS in the menu bar along the top of the window The window shown in Figure 11 14 will appear Click the plus sign at the bottom of the DNS Servers box and type the IP addresses of one or more DNS servers You should obtain these addresses from your Internet service provider Click OK to save your changes and close the Advanced Network window The main Network window will appear with your current settings in place Click the open padlock icon at the lower left corner of the window to lock the settings and then click Apply to save your settings and close the Network window N00 Network Built in Ethernet TCP IP DNSH WINS AppleTalk 802 1X Proxies Ethernet i DNS Servers Search Domains 192 168 0 1 domain actdsltmp 64 255 237 242 64 255 237 243 IPv4 or IPv6 addresses EM e Cem OR J Figure 11 14 Enter the addresses of your ISP s DNS servers in the DN
115. S F lt f on Tower Computer Tower ig g on Tower Computer Tower t ig h on Tower Computer Tower os L Bi on Tower Computer Tower khalinstal MSDOS NTDETEC ntldr al bf z 29 objects 780 MB W Internet Figure 1 1 The files and folders on a remote computer are easy to reach through a network Of course you probably have some files on your own computer that you don t want to share personal letters confidential financial records medical information and so forth A well designed file sharing system allows each user to set every file or folder as either public or private For more about sharing files with other computers on your home or office network see Chapter 12 How a Network Will Improve Your life 5 Chapter 1 Sharing an Internet Connection When you order a connection to the Internet the telephone company or the cable TV company installs just one connection point It doesn t matter if the Internet service uses a dial up telephone line a high speed DSL line a cable TV service a fiber optic link or some kind of radio link your Internet service terminates in just one place most often in a piece of electronic equipment called a modem that s geek speak for modulator demodulator a device that converts between computer data and some other type of communications signal If you have just one computer you can connect it directly to the modem but when you want to conn
116. S attack occurs when your network receives a very large number of incoming connection attempts that overloads the network s capacity to respond The volume of traffic forces the computers and routers in the network to operate at or beyond their capacity which causes them to either flood the network with useless traffic disrupt connections among machines or completely disrupt network service For example a mail bomb attack might generate tens of thousands of useless email messages A DoS attack can make it impossible to do anything else on the network or it can block legitimate incoming traffic such as requests for access to a web server or exchange of email Most DoS attacks are aimed at large businesses government agencies and educational institutions so they re not a common problem for home or small business networks Even so it s important to know how to recognize DoS attacks and how to deal with them US CERT the United States Computer Emergency Readiness Team has identified three basic types of DoS attack consumption of limited resources destruction or alteration of configuration information and physical destruction or alteration of network components If your small network suffers a DoS attack you re likely to see a significant deterioration of network performance or even a complete breakdown If somebody decides to target your network with a DoS attack you can t do much to discourage them Therefore your best protection is
117. S window Connecting Your Linux or Unix Computer to a Network Different Linux and Unix distributions use different network configuration programs but they all require the same information that Windows and Macintosh computers use to connect to a LAN and through the LAN to the Internet Like the network connections for Mac and Windows most Linux and Unix systems will automatically set up a connection when a DHCP server is active Figure 11 15 shows the Gnome Network Administration Tool provided with Ubuntu To change the settings select the Wired connection box and click Properties Network settings Location t JOE Connections General DNS Hosts a Wired connection s Properties rz Address dhcp Point to point connection This network interface is not configured Hep f e unlsd Eg close Figure 11 15 Gnome uses a tabbed window to set network configuration options Connecting Your Computer to a Network 127 128 Chapter 11 The DHCP control and the manual IP address and DNS settings are shown in the Properties window in Figure 11 16 This window includes fields for the usual numeric IP address subnet mask and default gateway address Sa eth Properties s Enable roaming mode Connection Settings Configuration Static IP address IP address 192 168 0 23 Subnet mask 255 255
118. Sam or Kate On the other hand the system for naming computers and networks connected to the Internet rather than to your own LAN follows some very specific rules called the Domain Name System DNS In the Domain Name System every name starts with a top level domain name at the extreme right that can be either a generic description such as com net or edu or a two letter country code such as wk for the United Kingdom or ca for Canada As you move to the left the next word or group of letters and numbers is aname called a subdomain that has been reserved by a specific owner an individual a business a government agency or some other formal or informal organization Large organizations might have one or more additional sub domain names to the left of the first one Each part of the name is divided from the next one by a period read as dot For example the University of Washington s domain name is washington edu Within the university the Department of Genome Science s address is gs washington edu And within that department the addresses of the research group studying evolutionary genetics is evolution gs washington edu At the extreme left of a domain name you will sometimes see a subdomain that identifies the type of server This address might be the familiar www or some other Internet service such as ftp file transfer protocol Many addresses also include the typeof Internet service the protocol that the
119. Sharing Before you can share files through a Mac you must turn on Windows file sharing From the Apple menu select System Preferences 2 Select View gt Sharing 3 Check Windows Sharing in the Service column as shown in Figure 12 14 The list of network preferences will now include Windows Sharing On eoo Sharing 4 Showall Q Computer Name Mr Bojangle s Computer Other computers on your local subnet can access your computer at Mr Bojangles Computer local Edit f Services Firewall Internet Select a service to change its settings On Service Windows Sharing On DVD or CD Sharing Stop v Personal File Sharing Windows Sharing Click Stop to prevent Windows users from accessing shared folders on this computer Personal Web Sharing This will also prevent Windows users from Remote Login printing to shared printers FTP Access Apple Remote Desktop You must enable an account to use Windows Sharing Enable Accounts Windows users can access your computer at 192 168 1 104 mrbojangles Remote Apple Events Printer Sharing i OO SBO amp a amp O 4 J 3 Click the lock to prevent further changes Figure 12 14 Select Windows Sharing in the Service column Connecting to Windows File Sharing To view or open a shared file on another computer through the network follow these steps 1 Click the Finder icon in the dock and select Connect to server from th
120. Some of this infor mation provides additional error checking and instructs the switching centers Types of Network Connections 11 12 Chapter 2 where to forward each packet while other information tells the destination device how to reassemble the data in the packet back into the original message The headers at the beginning of a packet and trailers at the end of a packet attached to each packet include the address of the packet s desti nation information that allows the recipient to confirm that the packet s content is accurate and information that the recipient uses to reassemble the packets in the original order Between the origin and the destination network routing equipment sometimes adds more headers or trailers that contain routing instructions and other administrative information Figure 2 2 shows how a network adds and removes headers and trailers at different stages of a communication session The specific names of the headers and trailer don t matter right now the point is that they surround the original data packet Original message Hast Transport E ER n me sec ihe Transport soma Figure 2 2 A data packet may be surrounded by several kinds of headers and footers That same pattern repeats every time you add another layer of activity to a communications system Each layer may attach additional information to the original message and strip off that information after it has done whatever
121. T I 3 Data Networks and What You Can Do with Them ssee A Pile SMGRING E E E fdancsua data E q 5 Sharing an Internet Connection sse eee 6 Instont Messages d e 7 Sharing Printers and Other Hardware sss 7 Home Entertainment ee e eene hee enhn esee se enses 7 Video Cameras and Home Security Devices ceccceceseeesceeeeeeeeeneeeenseeeaes 8 Home AUtOMatiOn ERN ER OE 8 2 TYPES OF NETWORK CONNECTIONS 9 Packets and Headers ssececcscssevsessescocccvsseccostentessevsesccenobevsececcantsecsessvececenssvess 11 xen 13 Handshaking and Overhead sss 13 E AAE UE Lue e AA e ee Eee 14 PME 16 Powerline Networks csssseeee eee eem Ihe ese ene re he isses ret r ss ess s sse ens 16 Other Alternative Wiring Methods sss eee 17 DTE and DCE Equipment eret tie eh etre rene to Phe ren EE Pee guam eo ORARE HERD ER Dod 18 Point to Point Networks sssseses eee eee nm em esses eret renes esee erret essen ena 19 P dale Bad MT Xs 20 WOO ERREUR 20 FireWire EEE T394 eese occae titia a a tins 21 Connections Through a Telephone line sssssse eee 21 Remote Terminals 52 ecce dusctete tes soos OUT EUR E E De e E ORO E Ove ERE costs Seve oes E ODE ERU QUEE 23 Clients and Servers sssssses Ie eee eee e sess s ert ret esses srt eter essen 23 3 HUBS SWITCHES AND ROUTERS 27 Hubs and Switches
122. The next sections explain how to deal with each of them DHCP Servers On or Off A DHCP server automatically assigns IP addresses and other configuration information to all of the devices in a network In a LAN the DHCP server is most often part of the router or modem that connects that network to the Internet or built into a network hub In most small networks using a DHCP server is more convenient than assigning a static IP address to each network device one at a time The DHCP setting is a common cause of connection problems If a com puter is configured to obtain its IP address and other settings from a DHCP server the DHCP server on the router or modem must be active Other less common DHCP problems can occur when more than one server is active at the same time In some cases the other network devices will obtain DHCP settings from the wrong server or the settings will not allow you to connect to the Internet If you can t successfully connect a computer to the Internet through your LAN when testing your network you should always check the DHCP server settings There are several important things to know about using DHCP in a LAN e A network can have just one active DHCP server e When a network is using a DHCP server each computer and other device such as a printer or game console connected to the network must be configured to accept an address from the DHCP server In Windows the Obtain an IP address automatically o
123. Vo Wireless adapter which is an optional accessory that connects to the DVR s USB port or a compatible adapter made by Belkin D Link Linksys or Netgear Connecting to a Wired Network To connect a TiVo to your existing wired network follow these steps Run an Ethernet cable from the DVR to a network hub or router 2 Press the TiVo button on the DVR and select Messages and Settings gt Settings Phone amp Network 3 From the Network Connection screen shown in Figure 15 6 select the Change network settings option sve Network Connection mpm Next attempt Sun 2 24 3 32 pm Network connection details Last pt Sun 2 38pm Type Ethernet connection Last status Succeeded IP addr 10 100 1 01 MAC ID 00 11 AA 22 33 44 Connect to the TiVo service now Use phone instead View network status Test TiVo service connection Figure 15 6 Use TiVo s Network Connection screen to configure a wired connection to your home network 4 Follow the instructions that appear on your screen If your network has an active DHCP server the TiVo client will detect it automatically and display a Network Setup Complete screen If your network doesn t have a DHCP server select No let me specify a static IP address and type an IP address for this network node the subnet mask and numeric addresses for the node s gateway router and DNS server 5 The DVR will test the connection If the settings are correct it will dis pla
124. Wi Fi Networks 83 84 Chapter 8 Photos courtesy of Linksys a division of Cisco Systems Inc Figure 8 5 USB Wi Fi adapters can be either stand alone devices left or small plug in modules right PCI Cards Wi Fi adapters on PCI expansion cards that mount inside a desktop computer are also available but they re less convenient than other types of adapters To install a PCI card you must open the computer s case and insert the adapter into an unused expansion slot on the computer s motherboard a considerably more complicated process than plugging in a PC card or a USB device The only reason to consider using a Wi Fi adapter on a PCI expansion card might be to add an old computer that has no USB ports to a wireless network Even then you could achieve the same result by installing an expansion card with several USB ports inside the computer and connecting a USB Wi Fi adapter to one of those ports That s probably the better approach because it will also allow you to use other USB devices with the same computer Antennas Every Wi Fi adapter comes with either a builtin antenna or an antenna that plugs into a socket on the adapter s case Some adapters include a builtin antenna and a socket As mentioned earlier in this chapter the antennas for a mini PCI adapter in a laptop computer are usually built inside the top part of the computer s case alongside the display panel Unless you re trying to send and receive Wi Fi signal
125. a small window on your desktop that contains the image from the camera in the other room Live conversations When both parties have a webcam and microphone connected to their computer it s easy to conduct a face to face conver sation through the network Remote conferencing One or more participants in a meeting or con ference can participate from a remote location Other Things You Can Connect to Your Network 205 206 Home Entertainment Networks A home entertainment system can distribute music TV movies and other audio and video through the same network that connects your household computers to one another and to the Internet Over the air cable or satellite TV and radio music from a CD player or stored on a hard drive and videos from DVDs can all provide source material for a system that can play music or display video in any room with a network connection There s a whole industry out there that supports very expensive home entertainment systems complete with video screening rooms the high tech popcorn maker is optional at extra cost TV screens built into walls or rising out of hidden cabinets in the kitchen or bedroom multiple speakers in every room and preprogrammed mood lighting But unless you have a spare 10 000 or 20 000 or more a lot more to spend on fancy equipment and custom installation those systems are not particularly practical Most of us will have to settle for something considerably le
126. adio signal from a nearby access point the adapter s control software will automatically match the signal type used by that access point Adapters Built into Laptops Built in Wi Fi interfaces are a standard feature of most new laptop computers The actual interface adapter is on a mini PCI card that mounts on the com puter s motherboard like the one shown in Figure 8 3 The antennas for internal Wi Fi adapters are usually flexible wires inside the upper half of a laptop s folding clamshell in the space surrounding the monitor screen Wi Fi Networks 81 82 Chapter 8 Antenna connectors Photo courtesy of Intel Figure 8 3 Mini PCI card Wi Fi adapters mount on the motherboard inside a laptop computer The Main and Aux connectors near the top in the photograph are antenna connectors One advantage of the mini PCI card approach as opposed to making the Wi Fi adapter a permanent part of the motherboard itself is that the adapter is what IBM calls a field replaceable unit FRU Other manufacturers use different names but the meaning is the same If an adapter goes bad or if you want to replace an older adapter with a new one that can handle new standards it s relatively easy to remove the old card and install a new one in its place without changing the motherboard This feature will be particularly convenient as and when the 802 11n standard becomes more common It s important to turn off the Wi Fi adapter whe
127. ail protocol 158 sneakernets 3 4 sniffer programs 178 179 249 social engineering 185 SoftRos Lan Messenger 235 Sony PlayStation 220 221 Sound Blaster 208 sound cards 205 208 211 212 Sound Forge Audio 208 sound quality 208 211 213 sources 206 207 SQL 95 Squeezebox devices 213 214 214 SSH Secure Shell 104 SSIDs Service Set Identifiers 86 90 177 179 178 183 244 283 SSL Secure Sockets Layer 89 164 176 standards wireless network 78 78 79 stars 27 static addresses 37 109 status indicators 75 stereo component music servers 208 stereo systems 206 212 storage servers 24 96 97 store and forward system 11 structured wiring center 59 63 subdomain names 39 subnet masks 42 109 113 118 128 superusers 226 surface boxes 55 56 surveillance monitors 205 S Video plugs 218 switches combination boxes 33 designing networks with 47 D Link 64 downstream 67 Ethernet 30 53 53 55 62 80 193 installing 59 61 62 64 63 location of 50 overview of 28 29 30 31 31 33 print 194 195 secondary 53 switching centers 11 Symantec Security Check 245 Synchronize It 232 SyncToy 232 system administrators 152 System Preferences window 124 INDEX 263 T TCO total cost of ownership 95 TCP See transmission control protocol TCP TCP IP 35 36 123 123 126 158 telephones line connections 17 18 21 22 22 64 65 65 wall outlets 48 49 51 wiring 17 18 tel
128. also print a copy of the current list including the date and keep it separately from the computer When it s time to add one or more additional devices consult the list to find and add a new address that isn t already assigned DNS Servers Your LAN needs one or more DNS servers to convert Internet addresses to numeric IP addresses but the DNS servers don t have to be part of the LAN you can use a DNS server anywhere on the Internet Use the same DNS server addresses for each computer that you used for the WAN side of the router If you can t get a DNS server address from your ISP run a web search for public DNS server to find addresses for alternative servers One widely used public DNS is OpenDNS http www openDNS com Gateways The gateway address is the address of the router or other control device that relays data between computers on a LAN and the Internet This gateway is sometimes called the default gateway The gateway address is the same as the numeric address used for the LAN side of the router Consult the router manual to find the correct address for your network Computers connected to the network don t use the same gateway address as the router or modem The router modem is the gateway between your network and the ISP s WAN Your ISP s gateway address identifies the path between their WAN and the rest of the Internet Configuring the Network Gateway The best place to find specific instructions for configu
129. ame or any other family name e Your favorite entertainer band team or song e Your own first initial and last name such as Smith e An obvious string of numbers letters or both such as 123456 abcxyz or abc123 e Your birthday or some other significant date e Your home town or country e Astring of characters from your keyboard such as qwerty or 96 e The word password e The phrase letmein that is let me in not the name of a Chinese noodle dish e The phrase trusinol Fox Mulder s password on The X Files TV series e The word swordfish originally used in the Marx Brothers Horse Feathers and in many subsequent movies books and computer games e The word sex or any common curse or obscenity e The word God or Jesus or any other deity of your choice e Any of these words or phrases spelled backward When a computer security expert in a movie or TV show finds the right password to break into the bad guy s computer on the third try he probably tried some of the passwords on this list Many network routers modems and other hardware come with default passwords preset at the factory These passwords are well known by crackers and easy to find in equipment manuals and on the Internet Network Security 153 154 Chapter 13 The best passwords are random strings of letters numbers and other characters at least seven or eight characters in length One expert tested a brute force password cracking program Ta
130. an set sharing permissions for each folder or individual file to allow read only or read and change access for specific users or groups of users A shared folder is also known as a network share or simply a share To share folders or files outside the Public folder follow these steps 1 From My Computer select one or more folders or drives that you want to share 2 Click Share in the toolbar at the top of the window The Share icon is only visible when you have selected one or more drives or folders it s not available for individual files The File Sharing dialog shown in Figure 12 7 will appear Sharing Files Through Your Network 139 22 File Sharing Choose people to share with People without a user account and password for this computer can access files you share with everyone To change this setting use the Net Name Permission Level R Everyone Contributor Y John Ross Owner v Th Unknown Contact Co owner Y Share Cancel Figure 12 7 The File Sharing dialog specifies the people with whom you can share a folder s contents To add an individual name to the list of people who have access to this folder click the arrow next to the empty field near the top of the dialog and either select that person s name from the list or select Create a new user from the drop down menu If you select Create a new user the User Accounts dialog will appear Select Manage another account and then select Create a ne
131. and NetBEUI networks IPsec is limited to IP networks Both the client and the server must use the same protocol In PPTP and L2TP the client and server must configure the tunnel for each transmission before they begin to exchange data The configuration parameters include the route through the intermediate network and the encryption and compression specifications When the transmission is com plete the client and server terminate the connection and close the tunnel Unfortunately several data security analysts have identified significant flaws in PPTP that allow intruders to break into a PPTP based VPN and sniff passwords and then decode encryption read data or inflict damage to a network server Therefore PPTP headers are not secure and should not be used In an IPsec network link the client and server must establish the tunnel through the intermediate networks in a separate transaction before they begin to exchange data Both L2TP and IPsec offer specific advantages and disadvantages but they re both good enough to create a secure link between a wireless network client and an access point The differences among the three are technical rather than practical You can find an excellent explanation of the internal operation of all three protocols in Microsoft s white paper entitled Virtual Private Networking in Windows 2000 An Overview which is available online at http technet microsoft com en us library bb 742566 aspx but reme
132. and onward to the nodes connected to those ports Each node compares the address on the packet with its own address and either accepts it if the address is the same or ignores it if the packet is addressed to some other node Because the hub sends each packet to every port only one packet can travel through the network at a time we re talking about many packets per second but they still move through the network one at a time If two or more computers try to send packets at exactly the same time Ethernet s collision detection feature forces them to stop wait and try again a fraction of a second later In order to prevent collisions each node must examine the network to be certain that no other node is already using the hub before it transmits a packet Therefore a network with a 10 100 hub is no faster than the slowest node If all the computers in your network use 100 Mbps network adapters but the printer connects through a 10 Mbps port the whole network will run at only 10 Mbps or less Hubs Switches and Routers 29 As more nodes try to use a hub at the same time the data transfer speed through the entire network drops This could have a significant effect on a busy network that uses a hub The actual data transfer could be only a fraction of the nominal 10 Mbps or 100 Mbps In general hubs are slow simple and cheap But the difference in cost between a hub and a switch is often insignificant so a switch is almost always the b
133. any When you re building a wireless network that will use network adapters made by different manufacturers or if you plan to allow users of laptops and other portable devices to connect to your network there s not much benefit to having an enhanced network The Wi Fi Alliance http www wi fi org the industry group that promotes these networks conducts periodic bake offs where many manu facturers demonstrate that their products will work correctly with equipment made by their competitors A network adapter or access point that carries the Wi Fi logo has been tested and certified for compatibility by the Wi Fi Alliance Operating Channels Wi Fi uses a segment of the radio spectrum also called a band near 2 4 GHz that has been reserved for unlicensed industrial scientific and medical ISM services including wireless data networks 802 11b 802 11g and 802 11n all use this band of frequencies 802 11a uses a different frequency band near 5 2 GHz known as the Unlicensed National Information Infrastructure U NII Both the ISM and U NII bands are open to many kinds of unlicensed radio services This means that the people who make the equipment must demonstrate that their designs meet various regulations related to maximum power interference and so forth but actual users that s you and me don t need to obtain licenses before they can operate approved radios One result of this is that the same radio frequencies used by Wi F
134. appears to connect two participants computers directly to each other so you specify the name of the other participant rather then the channel After you make the initial connection there s not much difference between chat and IM Servers vs Peer to Peer Messaging Instant messaging services can use two different structures through message servers that receive all messages and forward them to their ultimate destina tions and peer to peer systems that forward each message directly from its source to its destination Figure 16 6 shows both types Just about every Internet based IM service uses a server messaging services within a LAN are usually peer to peer FFA TC Internet LA message User 1 Ethernet Internet IM Service Peer to peer Figure 16 6 Internet instant messaging servers and peer to peer chat use different structures to accomplish similar objectives Internet Based IM Services Most IM uses one of the services that send and receive messages through the Internet such as AOL Instant Messaging AIM Windows Live Messenger Google Talk or Yahoo Messenger or a service that exchanges messages with a mobile telephone Other messaging programs are available that operate within a LAN Unfortunately many IM services are self contained networks for example you can t use Google Talk software to send a message to an AIM account However several third party programs such as Pidgin hitp wuw pidgin
135. arded Windows fire wall software products There s also a firewall built into Windows XP and Windows Vista that is adequate for most home and small business networks Linux and Unix users also have plenty of firewall options Most of them were written for stand alone firewall computers that are commonly used as network gateways but they could be equally appropriate as protection for individual network clients In Linux the iptables firewall is part of the kernel It s well documented at hitp www netfilter org projects iptables index html Port Scan Attack Detector psad is another set of tools that identify port scans and other intrusions on many Linux systems For more information see http www cipherdyne org psad IP Filter is a software package that provides firewall services to FreeBSD and NetBSD systems The official IP Filter website is hitp coombs anu edu au avalon and you can download an excellent HOWTO document at hitp www obfuscation org ip ipf howto txt The program can deny or permit any packet from passing through the firewall and it can filter by netmask or host address establish service port restrictions and provide NAT services OpenBSD FreeBSD and NetBSD can all use the Packet Filter or PF facility to perform firewalling More information is available at http www openbsd org faq pf NetBSD 1386 Firewall is another free Unix firewall It will operate on any PC with a 486 or later CPU and as litt
136. at already exist on the other side it only copies the changed bytes Server side programs run on the server and collect backups from each client computer BackupPC is a good choice as a server side Linux backup program because it can back up Windows Linux and Mac computers through a network BackupPC is available for download from hitp backuppc sourceforge net Amanda the Advanced Maryland Automatic Network Disk Archiver hittp www amanda org is another server side backup program that supports Windows and multiple versions of Linux and Unix Using a Server at Home A server on a home network can do all the same things that a server on a business network can do but many of those business functions are probably not particularly important at home A typical home network server is mainly useful for storing and sharing files such as music and videos making auto matic backups and maybe hosting web pages and email However a local server is not always the best way to manage email or host web pages Using the hosting services that are included with your Internet connection is often easier a good hosting service will handle all of the security issues and other maintenance for you Many Internet service providers will give you a separate email address for each family member and provide space on an existing web server for your family s web pages Or if you prefer you can obtain individual addresses from one or more of the free
137. authentication option that uses encryption when a network client has the key but uses unencrypted data with other network nodes Mixing Hex and ASCII Keys Setting up a mixed network becomes more complicated when some network nodes use hex only and others require ASCII keys If that s the situation on your network you will want to follow these rules for setting the encryption keys e Convert all your ASCII keys to hex Ifa configuration program demands an ASCII key enter the characters Ox zero followed by lowercase letter x followed by the hex string If you re using Apple s AirPort software you ll have to enter a dollar sign at the beginning of a hex key e Make sure all your encryption keys have exactly the right number of characters Network Security 181 182 Chapter 13 e Ifall else fails read the security sections of the manuals for your network adapters and access points It s possible that one or more of the devices in your network might have some obscure proprietary feature that you don t know about WPA Encryption WPA encryption was developed as a partial solution to the security problems that make WEP encryption less than totally secure WPA is much safer than WEP but cracking WPA is still possible WPA is more secure because it uses a method called Temporal Key Integrity Protocol TKIP to automatically change the encryption key after a specified period of time or after the system exchanges a spec
138. ay in downtown Seattle Completing that echo takes longer but it s still pretty fast Lines 4 to 7 show the packets moving through various routers in the same switching center in Seattle Starting at line 8 the route apparently jumps through routers in Chicago Kansas City Fort Worth and Dallas which increases the response times The path moves around a routing center in Dallas at lines 11 through 15 until it ends up at the Laughing Squid web host that houses the No Starch web server This connection goes from origin to destination with several thousand miles of detours However the whole thing takes only about a tenth of a second so those detours don t really matter TraceRoute can help identify several possible problems If a TraceRoute report ends with one or more lines of asterisks that usually isolates the problem to either the router named in the preceding line or the connection from that router to the next one If the report shows a very long path that includes router addresses that don t seem to be a on a reasonable route such as a path from New York to Philadelphia by way of Singapore one of the network routers is not configured correctly If the route shows that a pair of routers are passing the signal back and forth until TraceRoute times out that usually indicates that one of those routers has lost a connection and is returning the signal back to the pre vious router That router still thinks th
139. based online community that runs on a Unix host computer in Sacramento California The Well s computer treated my desktop computer in Seattle exactly the same as it would treat a local terminal connected directly to the host You might see similar text based host computer displays from library catalogs or mainframe computers Connected 9 32 PM 2 10 2008 1i This is The WELL Find membership information at http www well com Forgot your password Go to http ww well com newpass If you already have a WELL account type your username login Password Last login Sun Feb 10 17 17 11 from iiss Figure 2 11 A remote terminal allows a user to operate a remote computer through a network You can connect to a computer as a remote terminal through the Internet using a category of programs called telnet that form the core of most terminal emulators or you can connect directly to the host computer through a modem and a conventional dial out telephone line Clients and Servers As your network grows you might choose to add some computers and other devices such as printers to the network Those additional computers will provide useful resources to all of the network s users In a network a clientis a computer or program that uses resources supplied by another device a serveris the device that provides those resources Organizing a network into clients and servers is one way to make that network much mo
140. ble 13 1 shows the amount of time that one programmer Jimmy Ruska needed to discover passwords of different lengths by creating and testing every possible combination The specific numbers in this table apply only to his particular program You should pay attention to how the amount of time increases as you add more characters to a password rather than the exact times The time to crack is even greater if your password includes one or more symbols such as amp and Table 13 1 Time to Test All Possible Passwords Password Length Letters Only Letters and Numbers 3 characters 1 second 2 seconds 4 characters 3 seconds 10 seconds 5 characters 1 minute 17 seconds 6 minutes 6 characters 26 minutes 3 hours 30 minutes 7 characters 14 hours 6 days 8 characters 15 days 205 days Source http blog jimmyr com Most Common Passwords 20 2008 php Other cracking methods can be slower or faster but the general point that longer passwords are more difficult to crack still applies Firewalls A firewallis a server that uses a set of rules established by the network manager to inspect incoming data and to block data from a source that isn t on a list or files that match a particular description such as a virus Or the firewall might pass all data moving from the LAN o the Internet but only allow certain types of data from the Internet The most common use of a firewall in a LAN is at the gateway to the Internet as shown i
141. broadband and WiMAX networks might be more secure than Wi Fi primarily because capturing data from them is more difficult and WPA encryption is better than WEP encryption no wireless security is perfect Encryption and other security methods can make data a little more difficult to steal but these methods don t provide complete protection against a really dedicated snoop As any police officer will tell you locks are great for keeping out honest people but serious thieves know how to get past them To make things even more dangerous many network managers and home wireless users leave the doors and windows to their networks wide open to intruders by failing to use encryption and the other security features that are built into every Wi Fi access point and network node Drive by logins to unprotected private networks are possible in many urban and suburban business districts and in a surprising number of residential neighborhoods Most people have gotten the message about using encryption on their home and office networks but too many of them are still using the older WEP encryption system rather than the much more secure WPA method The technical support people at one major telephone company Qwest were still advising their DSL customers to use WEP encryption as late as mid 2007 If you re located in a city center or a suburb you can probably see this for yourself When you use your Wi Fi control program to scan the networks in your
142. builtin Ethernet port must use a network adapter on a plug in PC card that fits into the PCMCIA socket on the side of the computer Figure 7 4 shows a network adapter on a PC card A new standard for 32 bit PC cards and services called CardBus was adopted in 1995 CardBus PC cards with a gold grounding strip next to the 68 hole connector don t fit older 16 bit PC card sockets but 16 bit cards will fit into 32 bit sockets If your laptop was made before 1997 look for a 16 bit 10 100 Mbps PC card adapter Very old laptops that don t have PC card sockets can connect to an Ethernet network through a serial to Ethernet adapter but it s probably not worth the effort Any laptop without a PC card socket is at least a dozen years old and it won t come close to the performance of today s least expensive models Considering that a serial to Ethernet adapter is likely to cost almost as much as a whole new computer it s time to replace your Old Faithful antique instead Ethernet Network Interfaces 73 74 NOTE Chapter 7 Figure 7 4 This 16 bit PC card network adapter uses a short cable sometimes called a dongle to connect the adapter to an Ethernet socket Finding the Driver Software for Your Adapter Windows XP Windows Vista Mac OS X and most current versions of Linux and Unix can automatically detect new network adapters In some cases you might have to restart the computer after installing the network adapter but in general t
143. can expect if to continue to do so unless you try to expand or otherwise improve it This is a classic example of If it ain t broke don t fix it On the other hand if you have an old desktop computer with some other kind of network interface or no network adapter at all you can probably connect it to your Ethernet LAN if you don t mind opening up the computer and swapping circuit cards Look for an Ethernet network interface adapter on a plug in card that fits one of the empty expansion slots and download the latest driver software from the card manufacturer s website Wi Fi short for wireless fidelity is a category of networks that use radio signals instead of wires to connect computers and other devices Another name for Wi Fi is wireless Ethernet because Wi Fi uses many of the same data handling rules and specifications as a wired Ethernet network However every Wi Fi packet must include additional handshaking data so the overall data transfer speed is often slower than a conventional Ethernet link Wi Fi offers several advantages It doesn t need cables to connect every network node so it s often easier to install and use than a wired network connection Rather than string cables through walls and provide a network outlet at every desk you can distribute access to the network through antennas in between each computer and a base station an access point in a central location When you travel with a laptop computer a handheld
144. cannot be decrypted by the network s WEP key Therefore the WEP settings must be exactly the same on every access point and client adapter in the network This sounds simple enough but it can get confusing because manufacturers use different methods to identify the size and format of a WEP key The functions don t change from one brand to another but identical settings don t always have identical descriptions Network Security 179 180 Chapter 13 How Many Bits in Your Encryption Key A WEP key can have either 64 bits or 128 bits Although 128 bit keys are more difficult to crack but they are still pretty insecure they also increase the amount of time needed to transmit each packet However confusion arises because a 40 bit WEP key is the same as a 64 bit WEP key and a 104 bit key is the same as a 128 bit key The standard 64 bit WEP key is a string that includes an internally generated 24 bit initialization vector and a 40 bit secret key assigned by the network manager Some manufacturers specifications and configuration programs call this 64 bit encryption but others describe it as 40 bit encryption Either way the encryption scheme is the same so an adapter that uses 40 bit encryption is fully compatible with an access point or another adapter that uses 64 bit encryption Many network adapters and access points also include a strong encryption option that uses a 128 bit key Devices that support strong encryption are downwa
145. center e Troubleshoot network slowdowns and failures No matter which operating system you use and even if you ve never installed or run a network before you ll get what you need to know in Network Know How ABOUT THE AUTHOR John Ross has worked on wired and wireless network ing for Motorola AT amp T and other manufacturers He is the author of more than two dozen books including Internet Power Tools Random House Connecting with Windows Sybex Wiring Home Networks Sunset Books and The Book of Wireless No Starch Press COVERS WINDOWS MAC OS X AND LINUX 29 95 29 95 0m 95 29 95 CDN NI 3ATIHS J
146. ces connected to LANs Because these addresses are only visible within each LAN it s practical to use the same addresses in different networks Every computer and every other device connected to your network must have a different address within one of these reserved number ranges Each network device including the LAN side of the router itself must have a different IP address from one of the reserved groups A DHCP server usually part of the router or modem will take care of this automatically and assign new addresses whenever users connect another computer to the network This can be especially convenient if users connect and disconnect laptops and other portable devices to and from the network If you re not using a DHCP server you ll have to set the address for each device one machine at a time The LAN side of your router or modem usually has a default address that you use to reach its configuration utility look in the device s manual to find the address You do not have to change the default address on a router or other control device unless another device such as a Wi Fi access point has the same default address To make sure that you haven t assigned the same address to more than one device keep a master list of IP addresses that includes every device connected to the network including laptops and other portable devices that use part time connections You can keep the list in a text file stored on your own computer but you should
147. ch a repair person before the problem turns into a catastrophic failure Remember the classic science fiction nightmare in which all your house hold appliances communicate with one another and conspire to take over your life When you connect everything to your home network that fantasy is one step closer to reality Several specifications for networked home appliances have been estab lished in order to assure that appliances made by different manufacturers will communicate with one another through a home network including the Living Network Control Protocol LnCP developed by LG Electronics and adopted by several other mostly Korean manufacturers and the Association for Home Appliance Manufacturers AHAM standard for Connected Home Appliances CHA 1 It s too early to know whether LnCP CHA 1 or some other specification will ultimately emerge as an industry wide standard but it s likely that some method for exchanging data among appliances and other devices through a home network will become common within the next few years If you buy a network compatible smart home appliance today it will probably use an Ethernet port to connect to your home network Depending on the specific applications built into each appliance it might use a control panel or remote control unit dedicated client software or a web based interface to run the appliance s communications functions Home Automation Other home network applications ca
148. ches of the plastic jacket from the end of the telephone cable If the outlet block has screw terminals strip about half an inch of insulation off the end of each wire and wrap the bare end around the screw next to the letter that corresponds to the wire s color If the terminal uses two vertical pins with a slot between them to hold each wire don t strip the wires but use a punch down tool to force each wire between the pins If your terminal does not come with a small punch down tool look for one ata home center or hardware store you will need the same tool to connect data cables to their outlet connectors If excess wire extends from the side of the connector cut it off When all four wires are connected place the dust cover on the plug After you have connected the telephone line to the outlet block plug in a telephone with a modular RJ 11 cable to test for a dial tone If there s no dial tone check your connections at both ends if you have a dial tone unplug the telephone set and use one of the cables supplied with the modem to connect the modem to the telephone line Connecting a TV Cable Most video wiring inside a building uses coaxial cable called RG6 U with a central copper wire surrounded by insulation and a metal shield The connectors that attach to this cable are called F connectors Video cables usually require a special tool to attach the F connector to each end of the cable If you re not installing your own vide
149. cial records email music and video maybe some games and a connection to the Internet It s all in one place Love it or hate it that computer has become an important part of the way you work and play In fact it s so important and so convenient that you eventually decide to add another computer it might be a laptop that you can carry from one place to another or maybe a second desktop machine that allows more than one person to use a computer at the same time And that s when the trouble starts Shortly after you get that additional computer you will discover that something a text file or a picture you need for a report or a music file you want to play or the modem that connects you to the Internet is located on the other computer You have to copy files to a portable disk or a flash drive when you have something to print and carry it to the computer connected to your printer when you want to scan something you must go to the computer NOTE with the scanner and when you want to connect to the Internet you must either use the computer with the high speed connection or wait until another family member has finished using the telephone so you can dial in Using the computer has risen to a whole new level of inconvenience Any time you or your family or business use more than one computer something you want a file a printer or some other resource is likely to be located on or connected to the computer you re not currently usin
150. configure your network gateway and before you can connect a computer to the Internet through that gateway you must configure that computer s Internet settings 108 The Internet From the Cloud to You Chapter 10 Network diagrams traditionally show the Internet as a big cloud Inside that cloud are millions of computers routers and other equipment located all over the world but the internal operation of that equipment is Somebody Else s Problem when you re hooking up your own network the Internet is simply a huge shapeless thing that performs in a predictable manner Figure 10 1 shows the connection from the Internet through your local network to individual computers Those computers can be any kind of network attached device such as a printer a network attached storage NAS device disk drive or a pocket size smartphone but for the sake of this discussion let s think of all those things as types of computers In order to send and receive data between your computer and the Internet you must supply certain information to the Internet and the Internet provides other information to you s customer s LAN C Als Cs Desktop computer Your ISP s Your Laptop WAN host router computer lt S Another k customer s LAN af Server Figure 10 1 The Internet communicates with your computer through a local network The Modem Your LAN probably connects to the Internet through a high speed telephone line or a cabl
151. ctly to the network as a separate node a printer server or through one of the network s computers Look for information about both types of printer connections in Chapter 14 Home Entertainment The same home network that carries data to computers can also distribute music movies and other audio and video to stereo systems TVs and home entertainment centers throughout the house Special purpose computers called music servers can copy music from CDs or older recordings such as cassettes or vinyl records or download music files store the music as digital files and play them in any room in the house on demand either through the speakers attached to a computer through a traditional stereo system or through a dedicated tabletop device similar to a radio The same players can also receive and play streaming radio stations from around the world through the Internet Video servers can store movies and other videos and make them available through the network to computers televisions and How a Network Will Improve Your life 7 Chapter 1 home theater systems Some network music servers also include docking stations for iPods and other portable music players that can transfer files between the server and the portable unit and play music and videos directly from the portable device Audio and video programs can move through the network at the same time as email web surfing and instant messages For detailed information about setting up and
152. d at the other end and IP Internet protocol which provides the rules that guide each data packet through different kinds of networks to the correct destination Your computer handles transmission control automatically so you don t have to devote a lot of attention to individual data packets and their contents The information in Chapter 2 of this book provides as much detail as most users ever need But the Internet protocol is another matter you should understand how your network and just about every other network connected to the Internet uses names and addresses for individual computers and other network nodes and how to use some of the standard software tools that are included in every network computer Fortunately internal routing through the Internet is automatic if you enter a valid address in your web browser email client or other program the Internet will almost always find a path to the computer with that address If it doesn t the ping and traceroute commands described in Network Tools on page 41 will help you find the source of the problem Names and Addresses An addressing convention sounds like an event where people attend speeches and workshops about house numbers and receive awards for send ing out five million pieces of junk mail without an error The formal sessions are often boring but the after hours parties are great In networks addressing conventions are actually the rules that everybody uses t
153. d your computer can detect other computers when network discovery is off the computer can t see other computers and other users can t see yours In other words network discovery is one more setting that must be turned on in order to view files among computers You might also encounter a custom state if a firewall exception has been disabled or one of the services that controls network discovery is not active To turn network discovery on or off from the Network and Sharing Center click the On or Off button or click the arrow at the far right of the Network discovery option then click the Turn On or Turn Off button and click Apply File Sharing Vista allows two kinds of file sharing through a network sharing from the Public folder and sharing from any folder You must turn on either method in the Network and Sharing Center before you can use it Sharing Files Through Your Network 137 138 Chapter 12 Public Folder Sharing When you turn on Public folder sharing from the Network and Sharing Center any folder or file within the Public folder is accessible to anyone on the network You can set the Public folder to allow read only access or you can allow any user to create new files and to read change and delete existing ones as shown in Figure 12 5 but you can t set different access levels to the Public folder for specific users the Public folder is an all or nothing or more accurately an everybody or nobody deal
154. dapter the network manager must add one more MAC address to the list This task is probably manage able in a home or small office network but it could be a major undertaking for a larger corporate or campus wide system if it s practical at all MAC authentication does not provide unbreakable protection against unauthorized users because a determined cracker could monitor radio signals from approved users intercept their adapters MAC addresses and load an approved address onto a different adapter But combined with encryption and other security tools authentication adds one more impediment in the path of a network cracker Every access point configuration utility uses a different format for its access lists The manual and online documentation supplied with your access point should provide detailed instructions for creating and maintaining an access control list The Wi Fi standards do not specify a maximum size for an access point s access control list so the numbers are all over the map Some access points limit the list to a few dozen entries but others such as the Proxim Harmony AP Controller will support as many as 10 000 separate addresses Still others accept an effectively unlimited number If you plan to use a list of addresses to control access to your network make sure your access point will work with alarge enough list to support all of your users with enough expansion space for future growth As a rule of thumb the access
155. de or a description of the location or the type of device at that node On some networks the name is a number or a combination of letters numbers and other characters that have no obvious meaning outside of the network a telephone number is a good example of this type of name In order to allow the network to accurately find each node it s essential that every name be unique Sneakernet The simplest kind of computer network is no network at all If you have been working with multiple computers without a network you know the routine Every time you need something from a different computer you have to store a file on a floppy disk a portable drive or a flash drive physically carry it from one computer to another and load the file onto the second computer Sometimes you ll take the file from the computer you were originally using to the one that is connected to the right printer If you ve been writing a paper on a laptop computer you might want to add an image that s stored on the desktop system s hard drive Or maybe you want to give a copy to a How a Network Will Improve Your life 3 colleague for review or approval Whatever the reason you have to carry a copy of one or more computer files from one machine to another This usually involves some walking so the process is often known as sneakernet The name reflects the informal dress common in most computer centers but if you and your family dress for dinner every evening
156. details about your network connection add all to the command as shown in Listing 4 2 C v IPConfig all Windows IP Configuration Host Name Primary Dns Suffix Node Type 2 2 252 IP Routing Enabled WINS Proxy Enabled DNS Suffix Search List Ethernet adapter Local Area Connection Connection specific DNS Suffix Description Connection Physical Address Dhcp Enabled Autoconfiguration Enabled IP Address 4 e Subnet Mask Default Gateway DHCP Server ee ee DNS Servers 2 2 2 ee ee Lease Obtained Lease Expires No No 1 domain actdsltmp 1 Intel R PRO 100 VE Network 1 00 0C F1 AA BF BF 1 192 168 1 100 1 255 255 255 0 1 192 168 1 1 1 192 168 1 1 1 198 137 231 1 206 63 63 1 Wednesday April 08 2009 3 11 22 PM Friday April 10 2009 3 11 22 PM Listing 4 2 The IPConfig all command displays additional information about your connection 42 Chapter 4 Obviously this command produces a lot more information The Host Name is the name that this computer uses on the LAN The Description identifies the type of network interface adapter that connects this computer to the network The Physical Address is the MAC address the unique hardware identifier of the network adapter The DHCP Server is the add
157. devote enough time and effort to monitoring Wi Fi signals can probably find a way to intercept and read the data they carry If you send confidential information through a wireless link an eavesdropper can copy it unless the website or other host is using an end to end encryption scheme such as SSL Credit card numbers account passwords and other personal information are all vulnerable Encryption and other security methods can make data a little more difficult to steal but they don t provide complete protection against a really dedicated snoop An entire catalog of tools for cracking Wi Fi encryption is easy to find on the Internet As any police officer will tell you locks are great for keeping out honest people but serious thieves know how to get past them Wi Fi Networks 89 90 Chapter 8 There are two different kinds of security threats to a wireless network The first is the danger of an outsider connecting to your network without your knowledge or permission the second is the possibility that a dedicated eavesdropper can steal or modify data as you send and receive it Each represents a different potential problem and each requires a different approach to prevention and protection Although none of the encryption tools currently available can provide complete protection they can make life more difficult for most casual intruders And as long as the tools are out there you might as well use them A few techniques can discourage
158. dhall Security enabled wireless network WPA ep ACTIONTEC Security enabled wireless network Figure 8 6 The Wireless Network Connection program supplied with Windows detects nearby Wi Fi signals and sets up a new network connection Wi Fi Networks 87 Chapter 8 t Intel R PROSet Wireless File Tools Advanced Profiles Help Wireless networks found Select one and click Connect Wireless Networks 7 la la la la ACTIONTEC his network has security enabled Berg Home This network hes security enabled MASTERMIND This network has security enabled mcbright This network has security enabled SST PR 1 This network has security enabled a To manage profiles of previously connected wireless networks click the Profiles button soson Help Close Figure 8 7 Intel s wireless program provides the same infor mation as the Microsoft program but in a different format Both of these programs and similar programs supplied with other operating systems network adapters and computers can automatically remember the login and password information and other details of each Wi Fi network you use For example Figure 8 8 shows the Properties settings for a hotel s Wi Fi network The next time you try to connect to the same network the control program won t have to ask for a password again because this network profile is set to Automatic 4 Wireless Net
159. dial up telephone connection n extended network is a traditional VPN that happens to originate from a wireless network client The same VPN can also support connections that don t include a wireless segment and logins from public wireless services such as the ones at airports or coffee shops This setup is conventional for a VPN Local short range VPNs are interesting to people who operate wireless networks because they add another layer of security to wireless links Because the data moving between wireless clients and the network access point is encrypted using an algorithm that is more secure than WPA encryption it is unintelligible to any third party who might be monitoring the radio signal Because the VPN server won t accept data links at the access point from wireless clients that are not using the correct VPN drivers and passwords an intruder can t break into the network by associating a rogue client with the access point The goal of a wireless VPN is to protect the wireless link between the clients and the access point and to lock out unauthorized users Therefore the isolated and encrypted data can only move across a single room rather than over hundreds or thousands of miles Of course the access point might also relay VPN encoded data onward through the Internet to a network host in another location Figure 13 4 shows a wireless connection to a VPN The VPN server is located between the wireless access point and the host LAN
160. e Go menu 2 When the Connect to Server dialog appears either browse to find the share you want or type the address using this format smb lt ServerName gt lt ShareName gt 3 Click the Connect button to make the connection Connecting from Older Mac Versions Apple did not include SMB file sharing in Mac OS until OS X 10 2 You can use one of the Apple sharing services to share Mac files using older software with another computer through a network but the process is somewhat different To share files from OS X 10 1 or 10 2 with another computer on the same network select Go gt Connect to Server A list of other computers will appear Select the name of the computer that contains the files you want to use and click the Connect button To connect to another computer from OS 8 or 9 follow these steps From the Apple menu select the Chooser Click the AppleShare icon 3 Ifa list of AppleTalk Zones appears choose the zone that includes the computer you want to reach 4 Select the name of the computer that contains the file or other resource you want to open from the list and click the OK button File Sharing in Linux and Unix NOTE The latest Linux and Unix distributions all include support for Windows file sharing SMB protocols so sharing files with computers using other operating systems or other Linux Unix distributions should be easy The terminology is not always the same but if you understand the underly
161. e Therefore repeating your steps can often help identify and solve it Troubleshooting 243 244 Chapter 17 Keep Notes As you try to identify and solve a problem keep a record of what you have done Describe each problem you encounter and what you did to fix itin a simple log or notebook Note configuration settings websites that provide useful information and the exact location of any options or control programs that caused the problem or helped solve it Keep this on paper rather than in a text file stored on the computer so you will be able to access it if the computer breaks down again If the same problem appears again your log will tell you exactly what you did to fix it the first time rather than stepping through all the same unproductive troubleshooting techniques again you can go directly to the correct solution One excellent approach is to keep a network notebook in a loose leaf binder Among other things your notebook should include the following e The configuration settings and passwords for each modem router Wi Fi access point and other device connected to the network e The numeric IP addresses for your Internet connection DNS servers default gateway and subnet mask e The numeric addresses used by your LAN e The make model serial number and MAC address if you can find them of each hub switch router modem Wi Fi access point network adapter and other network device e Alist of channel numbers
162. e TV system The device that converts digital data to and from the LAN to signals that can move through the phone line or cable is a modem modulator demodulator In most cases the modem is combined with a gate way router but some cable TV companies and telephone companies provide stand alone modems that can connect either directly to a single computer or through a router or switch to a LAN For the purposes of this chapter you can think of a modem as a type of router The differences between a modem and a router are that a modem includes the internal hardware that performs modulation and demodulation activities along with the software that provides the connection settings The configuration settings that control the connections between the Internet and your local network are generally the same in both modems and routers NOTE A dial up modem that uses the voice telephone network to connect your computer to the Internet operates in a similar manner to a high speed modem but it uses a much slower connection The Gateway Router As Chapter 3 explained the router that connects the Internet to your local network has a point of presence in two different networks your Internet service provider s wide area network WAN and your own local area network LAN The WAN is part of the much larger Internet cloud Therefore the router has two different addresses one address on the WAN and a different address on the LAN The router s job is to e
163. e Windows Macintosh or Linux Unix operating system as well as on the network itself Define the Problem The first step in solving a problem should be to identify the symptoms Remember that computers and networks don t break down completely at random Every piece of information you can find about a problem can help you isolate and solve it Is the problem a failure to connect to a particular computer through the network or an error message or a file transfer that takes longer than usual Is it limited to a single computer or does it appear all over the network Have any of the lights on your network router switch or modem changed color or gone dark Does the problem occur when you are using a particular program or only when a certain desk lamp or vacuum cleaner or any other electrical device is turned on As you identify symptoms make a list either on paper or in your mind If you see an error message copy the exact text onto a piece of paper You might have to restart the computer or go to another computer to search for information and you will need the specific wording of the message Don t ignore the cryptic code numbers or other apparently unintelligible information Even if the message means nothing to you it could be the key to finding the help you need Sometimes you can identify a pattern in the symptoms When more than one user reports the same problem ask yourself what those users have in common Are they all trying to
164. e addresses of the DNS and WINS name servers used by this network Configure the remote access server as a router The server must use either static routes or routing protocols that make each VPN client reachable from the wired network Enable and configure the server for L2TP clients Windows uses Remote Access Service RAS and point to point protocol PPP to establish VPN connections The Routing and Remote Access service enables RAS A VPN connection requires the following RAS con figuration options Authentication method Encrypted PPTP connections use the MS CHAP or EAP TLS authentication methods Authentication provider Either Windows 2000 security or an external RADIUS server can verify network clients IP routing IP routing and IP based remote access must be active If the wired network acts as a DHCP server for the wireless clients DHCP must be active Network Security 163 164 Chapter 13 Configure L2TP ports Set each L2TP port to accept remote access Configure network filters Input and output filters keep the remote access server from sending and receiving data that does not originate at a VPN client These filters will reject data to or from unauthorized users so those intruders will not be able to obtain an Internet connection or a connection to the wired LAN through the wireless network Configure remote access policies Set the remote access permission for each VPN client to allow access to the RAS serve
165. e best path is through the other one so it tries again How Computer Networks Are Organized 45 46 Chapter 4 e Ifthe report shows a long delay that always begins at the same router it could indicate a problem with that router or very high demand for ser vice through that part of the Internet Unless you re a network manager you probably won t have to analyze TraceRoute reports very often But if you re having a connection problem they can sometimes help you to understand why you re not getting through to a website or instant message recipient DESIGNING YOUR NETWORK It s quite possible to construct a computer network on the fly stringing Ethernet cables from a central hub or switch to indi vidual computers and other devices as you need them But it s almost always better to spend some time planning your network before you start to install it It s a lot easier to make changes to your design on paper rather than making adds moves and changes in physical space This chapter offers advice and instructions for preparing a network plan I m assuming in this chapter that you have chosen not to use either power line or video cable as your primary network distribution medium Both of those methods can be practical in some situations but a traditional Ethernet system possibly with a supplementary Wi Fi base station is usually a better choice for a small business or household network because the equipm
166. e computer if you connect 10 computers the network is 100 times more powerful and so forth It s not an exaggeration to say that connecting your computers to a network will change your life Within just a few days or weeks you will begin to think about everything connected to the network other computers printers game consoles the Internet and anything else as an extension of your own keyboard and monitor And shortly after that you will discover new opportunities and services that a network makes possible In this chapter you will learn about the general nature of computer networks and the things you can do with them You can find more details about using a network later in this book What s a Network Chapter 1 Before we begin to consider the things you can do with a computer network it might be helpful to understand a few basic concepts First the idea of networks is not limited to computers A network can be any kind of structure that connects individual objects The highway system is a network and so is the worldwide telephone system You can use either of these networks to interact or communicate with other people connected to the same system Broadcasting networks such as CBS and the BBC use wires microwave radio links and other methods to distribute programs from one or more studios to a large number of local stations Every network has the following elements in common e Two or more objects or nodes that use
167. e direction When a data link sends and receives signals at the same time it must use separate wires to send data from the DTE to the DCE and from the DCE to the DTE Therefore a network device uses separate inputs and outputs on the same multipin connector The specific pin assignment is different in different connection types but the inputs and outputs are always different pins or sockets The problem arises because every output must connect to an input As Figure 2 5 shows if you connect an output to another output the two signals will collide if you connect an input to an input there s never any signal output collision output input I lt gt input E no signal Figure 2 5 Connect an output to an output or an input to an input and nothing useful happens Therefore when you connect two pieces of equipment the outputs at each end must go to inputs at the other end If Pin 2 on one device is an output Pin 2 on the other device must be an input Most standard data cables connect each connector pin to the same numbered pin at the other end so connecting two devices through a cable is exactly the same as plugging one device directly into another That s why there are two categories of data devices Data terminal equipment includes remote terminals computers some printers and other network endpoints Data communications equipment includes modems hubs switches and other control devices When y
168. e key looks the same to the computer either way but copying the string when it s broken apart is easier A passphrase is a string of text that the adapters and access points automatically convert to a string of hex characters Because humans can generally remember actual words or phrases more easily than hex gibberish a passphrase can be easier to distribute than a hex string However a pass phrase is only useful when all the adapters and access points in a network come from the same manufacturer D Link DI 713 Web Configuration Microsoft Internet Explorer zE File Edit View Favorites Tools Help O O AAG o Address http 192 168 0 1 z D Link Wireless Gateway ana 7 Wireless Setting Network ID SSID Local crane Security c Enable insecure access Enable IEEE 40 bit Shared Key security a2341789ff Save Undo Help Virtual Server Special AP Access Control Misc Items Wireless Basic _ Log out E Py pm A Figure 13 18 The configuration utility for a D Link access point accepts WEP keys in hex format What Are the Options Like just about everything else in a Wi Fi configuration utility the names of the encryption options are not consistent from one program to the next Some programs use a straightforward set of options such as enable WEP or WPA encryption but others use technical language taken from the formal 802 11 specification Some access points also offer a shared key
169. e network switch router or other control device Check the Settings and Options Look for other switches and settings that might interfere with a device s operation For example make sure that the network printer is online and that no Error LED indicators or messages are visible in the control panel Or if you re having trouble with a Wi Fi connection make sure your computer hasn t associated itself with the wrong base station and connected to one of your neighbors networks instead of your own Isolate the Problem If your search for simple solutions to a network problem or failure doesn t produce an answer the next step is to identify the physical location where the problem is occurring Although it s easy and often appropriate to think about a network as an amorphous cloud that exists everywhere at the same time when you re looking for a specific point of failure you must replace that cloud with a detailed map that shows every component and connection If you don t already have a network diagram in your files consider drawing one now Most problems offer some kind of hint about their location If just one computer s connection to the network has failed but all the others work properly the problem is probably in that computer or its network link But if nobody on the network can connect to any other computer or to the Internet the problem is probably in a server router or other central device Start searchin
170. e network through a single outlet as shown in Figure 5 5 Connecting through a switch can be particularly handy when you want to use two or more devices such as a computer and a game console or a printer server or two or more computers in the same room Desktop computer Printer server Switch Router Desktop computer Switch Laptop computer Figure 5 5 An Ethernet switch can extend a network to connect two or more devices to the network hub through a single cable A secondary switch can also be useful when you want to place network connection points in adjacent rooms that are difficult to reach from the control center For example if you have two second floor bedrooms that share a wall you could run a single cable to a switch and connect the switch to computers in both rooms Many Wi Fi access points are combined with switches that allow you to connect one or more devices to the network through wired Ethernet outlets If you locate your access point in a room where you also use a desktop com puter or other network device a combination unit is often an excellent choice Place the access point next to the computer and use an Ethernet cable to connect it to the switch Designing Your Network 53 54 What About Wi Fi Chapter 5 Connecting computers and other network devices through a Wi Fi network is often an easy alternative to a wired Ethernet system A single access point is often enough for sending and rec
171. e store or home center Follow the instructions on the package for gluing PVC pipes to fittings but don t worry about creating watertight seals Your network data won t leak through a bad pipe joint The Control Center Chapter 6 A network control center always performs these tasks e Itconnects the local network to the Internet through a modem and a telephone line cable TV service or some other medium e It uses a router to translate addresses between the LAN and the Internet e It uses a hub or a switch to exchange data within the network e Itacts as the central distribution point for data cables In addition it might also include these services e Abase station for Wi Fi e A distribution center for audio video and telephone connections If you re working from the floor plan you created after reading Chapter 5 you have already chosen a location for your control center If not find a place that is easy to reach but away from day to day traffic the inside wall of a walk in closet a utility room or a basement wall are all common choices A garage that s built into the house might be another good spot The control center should be close to at least one dual AC power outlet A network control center can take several forms A modular structured wiring center Several manufacturers offer structured wiring cabinets and most of the switches routers and other control devices necessary to assemble a network control cent
172. e the same for any backup program To use the Windows Backup program follow these steps 1 From the Windows Start menu select All Programs or Programs if you re using the Classic Start Menu Accessories System Tools gt Backup The Backup or Restore Wizard window shown in Figure 9 7 will open Backup or Restore Wizard x Welcome to the Backup or Restore Wizard This wizard helps you back up or restore the files and settings on your computer If you prefer you can switch to Advanced Mode to change the settings used for backup or restore This option is recommended for advanced users only Always start in wizard mode To continue click Next cma Figure 9 7 Use the Windows Backup or Restore Wizard to create backup copies of your files 2 Click Next to advance to the next screen The wizard will ask if you want to make new backups or restore files that you saved earlier Select the Back up file and settings option and click Next 3 The wizard will ask what you want to back up To save all the information on the computer select the All information option this option will allow you to create a new copy of the original hard disk but this copy takes up a lot of storage space To create a more selective backup select the Let me choose option 4 Click Next to advance to the next screen The wizard will ask where you want to store the backup File Servers 101 102 Chapter 9 5 Click the Browse b
173. e to reach all parts of a house or small office but if it doesn t because of obstructions or interference the best solution is to add a second or third access point at a location where its signal will fill in the dead spots Each access point should be connected to the wired portion of the network through an Ethernet hub or switch or if that s not practical through a wireless bridge that retransmits Wi Fi signals on a different channel In a Wi Fi network with more than one access point they should all use the same network name but each one should use a different non overlapping operating channel Photo courtesy of D Link Figure 8 2 This Wi Fi access point doubles as a network router Network Interface Adapters NOTE Wi Fi network interface adapters are small radio transceivers that convert from computer data to radio signals that they exchange with a Wi Fi access point and back again A Wi Fi adapter can be an expansion card inside a laptop or desktop computer a plug in PC card or a separate USB device A Wi Fi adapter can also exchange data by radio directly to and from another computer in an ad hoc network as described in Chapter 2 Most new Wi Fi adapters are compatible with all four standards 802 1 1a b g and n so they can exchange data with any Wi Fi access point Older adapters might use only one two or three standards so they ll only connect to compatible base stations When a network adapter detects a r
174. e while you watch the LED indicator that corresponds to that socket If the LED lights and goes dark as you shake the cable try a different cable If you can t connect through a newly installed wall outlet make sure the wires inside the outlet are connected to the correct terminals at both ends of the cable inside the wall at the outlet and at the data center To quickly confirm that data is passing through the network to and from each computer use the tools supplied with the computer s operating system to display network activity In Windows use the Networking tab in the Task Manager in Linux use the ethtool command ethtool interfacename grep Link If the computer reports that no link is available a cable is disconnected or the network adapter or hub has a problem Check the AC Power Every device connected to the network probably has an LED indicator that lights when the device is connected to AC power When a connection fails look at the front of each device to confirm the power light is on If it s not check the device s power switch if it has one and both the plug at the back of the device and the plug or power supply that plugs into the AC outlet If you use a power strip or an uninterruptible power supply make sure that the master power switch is turned on and the power unit is plugged into an AC outlet If the network fails but your computer still works a fuse or circuit breaker might have blown in the room containing th
175. ect two or more computers to the Internet at the same time you ll need a network For many families a high speed Internet connection provides the reason to start thinking about installing a home network When you spend that extra money for a DSL or cable Internet link or fiber optic link you want easy access to the Internet from every computer in the house When you connect your network to the modem through a gateway router shown in Figure 1 2 you can reach the Internet through any computer on that network Some modems require a separate router to distribute the Internet connection to multiple computers while others have built in routers Desktop computer Desktop computer Gateway DSL or cable router modem Laptop computer Tower PC Figure 1 2 A gateway router provides a connection between a local area network and the Internet Connecting your network to the Internet is not difficult but it s easier with detailed instructions You can find those instructions in Chapter 10 Instant Messages Instant message programs display text on a distant computer s screen almost as fast as you can type them They re useful for exchanging notes asking questions and nonspecific chatter within a business or between friends and family members When a new message arrives the messaging program pops up in a new window on the recipient s screen If you attach a microphone and speaker to each computer you can u
176. ection settings If the settings that appear in the Network window are not the ones you want to use click the padlock icon in the lower left corner of the window to change them The icon will change to an open padlock To change the network configuration settings click the Advanced button near the bottom of the window The Built in Ethernet window shown in Figure 11 12 will appear Built in Ethernet DNS WINS AppleTalk 802 1X Proxies Ethernet p Configure IPv4 Using DHCP d IPv4 Address 192 168 1 103 Renew DHCP Lease Subnet Mask 255 255 255 0 DHCP Client ID If required Router 192 168 1 1 Configure IPV6 Automatically sd Router IPv6 Address Prefix Length e Cm CO Figure 11 12 The Builtin Ethernet window controls the network configuration settings Connecting Your Computer to a Network 125 126 Chapter 11 10 11 12 The bar along the top of the window contains seven network options Click TCP IP to enter or change your Internet connection settings The Configure IPv4 field is a drop down menu Click the arrows at the right of the field to open the menu shown in Figure 11 13 NOM Network maw g Built in Ethernet f TCP IP DNS WINS AppleTalk 802 1X Proxies Ethernet Configure IPv Using DHCP with manual address IPv4 Address Using BootP Renew DHCP Lease Subnet Mask Manually ID If required Router or J a Configure I
177. eed a separate printer server device or a printer with a built in network server e You can locate a printer anywhere not just where you have a free net work port or outlet e Ona network where different users have different types of printers such as laser and inkjet color and black and white or special formats for photos or large documents using a computer as a printer server allows everyone to take advantage of each printer s features e You don t need an additional port on the network hub or router On the other hand this approach also has a few possible drawbacks e The computer acting as a printer server must be turned on whenever anybody wants to print this could be a security issue e When the printer begins to print without warning it could distract the person using the computer connected to the printer e As other users come into the office or workspace where the printer is located to collect their print jobs this can be yet another distraction for the operator of the computer acting as a printer server If your network also uses a dedicated file server you can eliminate the security and distraction issues by using the same computer as your network s printer server Or if you have an older computer collecting dust in a closet you can use it as a stand alone printer server although you might have to add a network interface and maybe a USB port on plug in expansion cards However the most common way to use a comput
178. eiving data to and from computers in many rooms A Wi Fi network can provide Internet access and LAN services but it has several disadvantages when compared with a wired network e Wi Fi networks are usually slower than wired Ethernet unless all the nodes in the network are compatible with the latest 802 11n standards e Wi Fi networks are less secure than wired networks Unless you protect your network with a secure encryption method such as WPA a dedicated intruder can connect to the Internet through your network without your permission and can also steal information from the other computers on the same network e Interference between your Wi Fi network and your neighbors networks and other wireless devices can reduce your network s data transfer speed In spite of those limitations a Wi Fi network is often an acceptable choice if you don t want to cut holes through your walls or spend time crawling through your attic or basement And even if you install a wired network through part of your building Wi Fi could be the best way to reach one or two isolated locations such as a top floor bedroom or a detached garage For many families and small businesses the best approach is to install both wired and wireless in the same network This will allow you and your users to connect your desktop computers printer music server and other devices that never physically move through wired Ethernet and use Wi Fi for laptop computers Voice over
179. eneenenee eene 240 Look for Simple Solutions First sss 241 Isolate the Problem 5 cte rti e ep ded 243 Refrace EO re 243 Keep Notes ciir eee ee Ra rt PE Pret eo ie REG IRR een 244 Viruses and Other N sti s 2 eei be ertet eb tere eH EET Le a nos 245 Other Common Problems 3 tete cete Lee pe ety bee ee egeo teg eee eg eet ee 245 Configuration Setfligs zu este pep CR E ERE RR Pec 246 DHCP Settings DNS and Default Gateway 246 Failed Connection to a Specific Site esccseseeseeceeeeeeteesteenteceteeneenteenaees 246 An Alternate Connection to the Internet 247 The Collective Wisdom of the Internet ssssssss 247 Software for Troubleshooting sss 248 Network Magic nii cc t eec i decet le f teat ce een 248 Protocol Analyzer 1 eiit ote iet He Dose e f e rite 248 ISP Problems e edt e e eet te cp et o d nw bier p eae dn 25 bodie one E 251 INDEX 253 Xil Contents in Detail ACKNOWLEDGMENTS A book like this is always a collaboration even if only one author s name is on the cover The book in your hands is a huge improvement over the original manuscript thanks to the efforts of editors Tyler Ortman and Kathleen Mish and copyeditors Eric Newman and LeeAnn Pickrell Technical editor Michael Kershaw protected me from embarrassing technical errors And compositor Riley Hoffman made this the attractive book you hold in your hands Thanks to all of you Of course any surviv
180. ent is widely available it s often inexpensive and it s easy to install and maintain To begin your network plan start with a floor plan of the house apartment or workspace where you want to install your network The plan doesn t have to be exactly to scale but it should be big enough to add notes within each room or cubicle and it should show the relative positions of each room Figure 5 1 shows a typical floor plan for a small one story house If it s convenient use a copier or scanner to make several copies of the floor plan T En BEDROOM STUDY LIVING ROOM T E 2 l A BATH 1 Oo KITCHEN oo BEDROOM mV r3 C LAUNDRY To T CELLAR Figure 5 1 Use a floor plan to identify locations for network connection points Identifying Current and Future Nodes The next step is to decide where you will want network connections Use different colors to note the locations of each of the following items Electrical outlets Network wiring and outlets should be at least 12 inches away from AC wiring so it will be helpful to identify all of the AC outlets in each room In addition you will want access to AC power for your computer router modem and other network hardware Your home entertainment systems Home theater equipment stereo systems televisions and game consoles can all exchange data through your home network so network outlets should be within close range Te
181. ential programs and files on a drive The backup programs provided with Windows Mac OS X and most versions of Linux and Unix are entirely adequate for most people but there are plenty of other backup programs with additional features and options often related to automatic scheduled backups Backup programs are often supplied with network attached storage NAS devices and external USB hard drives The important thing to remember about using any backup program is that you must store your backed up files separately from the originals You can store the backup on a second hard drive on the same computer not a good idea however because it doesn t protect against fire or theft on a set of CDs DVDs or data tapes or on a computer or other storage device connected to the original computer through a network or NOTE the Internet A network is a great way to move your backup data to another computer for storage but you will still want some kind of backup on removable media stored off site to protect your data from fire or theft The backup methods described in this chapter will work equally well on a network with out a designated file server you can use any other computer or network storage device on the same network as the destination for your backup files The Windows Backup Program Microsoft has supplied a backup program with most versions of Windows including XP and Vista This example uses Windows XP but the general principles ar
182. ephone line or some combination of those and other transmission media Network Security 159 160 Chapter 13 In a traditional VPN a remote user can log in to a distant LAN and obtain all the same network services that are available to local clients VPNs are commonly used to extend corporate networks to branch offices and to connect users to the LAN from home or from off site locations such as a client or customer s office A connection through a VPN server looks to the rest of the network exactly like a client device connected directly to the LAN The only difference is the data from the VPN passes through a VPN driver and a public network instead of moving directly from the network adapter to the LAN Figure 13 3 shows a typical VPN connection to a remote network Public network telephone line or Internet Remote computer with VPN driver Figure 13 3 A remote network can connect to a LAN through a virtual private network All of the same security benefits also apply to short range VPNs that tunnel through a wireless link and longer range VPNs that start on a wireless network and relay the data to a remote server These are two different uses for a VPN a local VPN that only extends across the wireless portion of a network between the client devices and the access point and an extended network that carries VPN encoded data beyond the access points to a VPN server through a public network such as the Internet or a
183. er The panel mounts on a wall or between the studs in an unfinished basement or garage and can include a cover to keep the contents clean and out of sight These panels and components are considerably more expensive than separate parts from different sources but they present a finished appearance that might be important if the control center is in a conspic uous location If you re using one of these systems follow the installation instructions supplied with each component A sheet of plywood attached to the wall A half sheet 4 feet by 4 feet of plywood securely bolted to wall studs is entirely adequate to support your network s mounting blocks control devices and other equipment It might not be as attractive as a structured wiring center but you re not going to see it very often If you do a neat workmanlike job it will work just as well as a fancy sheet metal cabinet full of matched components A freestanding mounting frame or cabinet If you have enough floor space in your utility room you can assemble the control center from equipment and shelves that mount in a 19 inch wide relay rack This approach is usually limited to larger networks that include a lot of loca tions and equipment Several wall mounted outlets and a small number of control devices modem router and or switch on a table or shelf If your network is limited to computers in just two or three rooms it might be easiest to choose one of those rooms as your contro
184. er as a printer server is to connect the printer to an existing computer and direct print commands from all the other computers in the network to print through the server In Windows setting up a printer server is a three step process described in the following sections Printers and Other Devices on Your Network 195 196 Chapter 14 Turning on Printer Sharing on the Network Card Follow these steps to turn on printer sharing on your network interface 4 From the Control Panel select Network Connections The Network Connections window will open Right click Local Area Connection and select Properties from the pop up menu To share through your wireless connection right click Wireless Network Connection Confirm that the File and Printer Sharing for Microsoft Networks option is active as shown in Figure 14 3 If you don t see a checkmark next to this option check the box to turn it on Local Area Connection 1 x General Advanced Connect using dB VIA Networking Velocity Family Giga Configure This connection uses the following items Client for Microsoft Networks a A Saos Packet Scheduler w I Pure Networks Device Discovery Driver Install Uninstall Propertie Description Allows other computers to access resources on your computer using a Microsoft network Show icon in notification area when connected V Notify me when this connection has limited or no connectivity Figure 14 3
185. er large object if you can t store it in a locked drawer or cabinet e Don t place your computer near a window where passers by can see exactly what you have e When you re away from home or work keep track of your laptop com puter at all times e Log off your office computer whenever you are about to leave your desk Don t allow other people to wander in and use your account when you re not there e Keep the login and password active on your laptop and use encryption for files that contain confidential data If somebody does steal the com puter you want it to be as difficult as possible for the thief to open and read your files e Install an antitheft alarm device on a PC card in your laptop or an inter nal card in a desktop system If somebody tries to move the computer disconnect cables or open the case without entering a security code first the alarm device will sound a very loud alarm e Use a tracking program such as LostPC hitp www lostpc com on your laptop computer The tracking software will automatically send a here I am signal to a security center every time it connects to the Internet from a new location Police and Internet service providers can some times use this information to locate and recover a stolen computer e Consider using full disk encryption tools such as TrueCrypt for Windows or dm crypt for Linux so the data on it is useless if your laptop is stolen Windows Update and Patches Mic
186. ers ssssssssssssseee eene 27 Chapter 4 How Computer Networks Are Organized sss 35 Chapter 5 Designing Your Network eem ee eene 47 Chapter 6 Installing the Network Control Center and Ethernet Cables ssssse 55 Chapter 7 Ethernet Network Interfaces sss 69 Chapter 8 Wi Fi Networks esses eem e em ee rere ener 77 Chapter 9 File Servers tee ertt eR HU e d RUE eoe deret Mee Ceo Od 93 Chapter 10 Connecting Your Network to the Internet sss 107 Chapter 11 Connecting Your Computer to a Network sss 117 Chapter 12 Sharing Files Through Your Network sss 131 Chapter 13 Network Security 2 5 cepto citur ep ce gei ee pel a ere EEE 151 Chapter 14 Printers and Other Devices on Your Network ses 191 www allitebooks com Chapter 15 Other Things You Can Connect to Your Network Audio Video Home Entertainment and Beyond sss emen 203 Chapter 16 Other Network Applications ssess ee 225 Chapter 17 Troubleshooting 1 reete e tete e e eene ke uia 239 D P vives 253 vi Brief Contents www allitebooks com CONTENTS IN DETAIL ACKNOWLEDGMENTS xiii INTRODUCTION xv 1 HOW A NETWORK WILL IMPROVE YOUR LIFE 1 What s a Network ccccccccsesecececcecceeseececcccusaavsccecceeesaaeasecccseussastececeeatnteeeeceeeanens 2 Smedkenmet E T
187. ers are computers on a network that hold text data and other files that all the other computers on the same network can use A file server can also be used as a work station a computer dedicated to file storage or a single purpose network attached storage NAS device This chapter describes the advantages of connecting one or more file servers to your network and explains how to set them up and use them File servers are much more common in business networks than at home but they can also be useful as part of a home network Whether at work or at home a server can provide these services e Itcan protect files on other computers connected to the network by automatically making and storing backup copies of those files e tcan store related files in a central location 94 e Itcan help control revisions and updates to documents and other files by assuring that everybody is using the same version e Itcan hold public files used by more than one person separate from each user s personal files e It can allow coworkers or family members to create and store new files or use existing ones without needing to turn on somebody else s computer e Itcan host web pages and other services for an intranet an Internet like site that can only be viewed within the local network e Itcan manage email distribution across the network e Itcan provide remote access to files through the Internet A server on a home network can al
188. es These files are not accessible through the network All Level 3 files and folders are located in the lt drive letter gt Documents and Settings All Users Shared Documents folder To assign a file or folder to Level 3 simply copy or drag it to the Shared Documents folder If you expect to create many Level 3 files and folders consider creating a shortcut to Shared Documents on the Windows Desktop Dragging an icon to a shortcut has the same effect as dragging a file or folder directly to the original folder Level 4 Level 4 drives files and folders are accessible through the network as read only documents Anybody with a network connection can open and read a Level 4 file but only the file owner and the administrator of the local com puter can change or delete the file To assign a drive folder or file to Level 4 follow these steps 1 From My Computer right click the icon of the drive or folder you want to assign to Level 4 A pop up menu will appear 2 Select Sharing and Security from the pop up menu A Properties window like the one in Figure 12 3 will appear with the Sharing tab visible System Drive C Properti 2 x General Tools Hardware Sharing Quota Local sharing and security is To share this folder with other users of this computer only drag it to the Shared Documents folder To make this folder and its subfolders private so that only you have access select the following check box va r Network shari
189. etter choice Switches A data switch performs the same function as a hub it connects the nodes of a network to one another but it does the job quite differently Rather than sending every packet to every port a switch reads the address section of each incoming packet and sets up a direct connection from the source of each packet to its destination In the meantime if some other node tries to send a data packet to another unused port the switch can set up the link without breaking the other connection As Figure 3 3 shows a switch can handle more than one connection at the same time Because a network node connected to a switch doesn t have to monitor the entire network for possible collisions it can send and receive data at the same time this is called full duplex mode Both of these features multiple segments and full duplex operation mean that data can move through a switch more quickly than through a hub a 0 6 i Desktop 1 Desktop i Laptop computer 1 computer 1 computer I l i I 1 3 Ethernet i switch i l TS Printer Figure 3 3 An Ethernet switch can support two or more simultaneous connections Data switches and hubs come in several sizes and shapes The smallest switches often have four five or eight ports inside a box that can sit on a table or shelf like the one shown in Figure 3 4 When your network expands 30 Chapter 3 www allitebooks com to need more ports than your original switc
190. etween them such as cost speed and coverage areas For readers setting up home networks the book contains useful advice about choosing and setting up hardware and software securing networks using WEP and WPA and setting up a wireless connection for VoIP JANUARY 2008 352 PP 29 95 ISBN 978 1 59327 169 5 THE MANCA GUIDE TO ELECTRICITY ELECTRICITY by KAZUHIRO FUJITAKI MATSUDA and TREND PRO CO LTD The Manga Guide to Electricity teaches readers the fundamentals of how elec tricity works through authentic Japanese manga Readers follow Rereko a denizen of Electopia the Land of Electricity as she is exiled to Tokyo to learn more about electricity In no time graduate student Hikaru is teaching her the essentials such as static electricity and Coloumb s law the relation ship between voltage resistance and current and the difference between series and parallel electrical circuits Using real world examples like flash lights and home appliances The Manga Guide to Electricity combines a whimsical story with real educational content so that readers will quickly master the core concepts of electricity with a minimum of frustration MARCH 2009 232 PP 19 95 ISBN 978 1 59327 197 8 PHONE EMAIL 800 420 7240 OR SALES NOSTARCH COM 415 863 9900 MONDAY THROUGH FRIDAY WEB 9 A M TO 5 P M PST WWW NOSTARCH COM COLOPHON The fonts used in Network Know How are New Baskerville Futura and Dogma The book was
191. etwork Attached Storage A network attached storage NAS device is a dedicated computer without a keyboard or display screen used as a network file server In the small business or home networks that many readers of this book are likely to have one or more NAS disk drives can be an entirely adequate alternative to a more expensive and complicated network server For all practical purposes a NAS drive is just a disk drive that connects to the network through an Ethernet port Several disk drive and network equip ment manufacturers offer purpose built NAS devices including complete hard drive assemblies and network storage enclosures for IDE or SATA hard drives Some NAS devices have both Ethernet and USB ports so you can use them with either a direct connection to your network or an external drive connected to a computer with or without a network link Figure 9 3 shows a network with a stand alone disk drive operating as a NAS device File Servers 97 98 Chapter 9 Stand alone disk drive Network attached Desktop computer Desktop computer Ethernet switch File server storage server Gateway router Figure 9 3 A network attached storage device connects directly to a network ANAS server could also be a regular computer with or without a key board and screen If you already have a spare computer to use as a server the FreeNAS version of FreeBSD shown in Figure 9 4 could provide all
192. f Steal This Computer Book contains new chapters that discuss the hacker mentality lock picking exploiting P2P file sharing networks and how people manipulate search engines and pop up ads Includes a CD with hundreds of megabytes of hack ing and security related programs that tie in to each chapter of the book MAY 2006 384 PP W CD 29 95 ISBN 978 1 59327 105 3 UBUNTU FOR NON GEEKS 3RD EDITION A Pain Free Project Based Get Things Done Guidebook by RICKFORD GRANT This newbie s guide to Ubuntu lets readers learn by doing Using immersion learning techniques favored by language courses step by step projects build upon earlier tutorial concepts stimulating the brain and increasing the reader s understanding This book covers all of the topics likely to be of interest to an average desktop user such as installing new software via Synaptic Internet connectivity working with removable storage devices printers and scanners and handling DVDs audio files and even iPods It also eases readers into the world of commands thus allowing them to work with Java Python or other script based applications convert RPMs to DEB files and compile software from source JUNE 2008 360 PP W cD 34 95 ISBN 978 1 59327 180 0 HACKING 2ND EDITION The Art of Exploitation by JON ERICKSON While many security books merely show how to run existing exploits Hacking The Art of Exploitation was the first book to explain how exploits act
193. f you have a total of seven nodes in your network you might use these control devices e ADSL or cable modem e A gateway router combined with a four port switch e A four port Ethernet switch Figure 6 6 shows how these devices connect to one another Desktop computer Desktop computer Server Desktop computer Desktop Laptop computer computer Figure 6 6 A network with seven nodes might use this setup in the control center You can find switches and routers at many office supply and electronics stores and through online retailers It seems as if one brand or another is almost always on sale so it s worth looking at the advertisements in the Sunday newspaper for this week s hot deals If possible your router or switch should have at least one spare port that you can use with a laptop computer When you re trying to troubleshoot the network it s often convenient to send commands from the computer while you watch the responses to those commands on the control devices status lights When you add more nodes to the network in the future you can expand the network by connecting an additional switch to the control center If there are no spare ports on the existing switch disconnect one cable from the active switch connect the new switch to that port and plug the original cable into the new switch Some switches and routers have keyhole slots on the bottom of their cases that allow you to mount them di
194. from scratch Once or twice every month is not too often to change keys in a home network An office LAN should change keys at least once a week Don t store your encryption keys in plain text on the network where they are used This seems self evident but in a widespread network it might be tempting to distribute the keys on a private web page or in a text file Don t do it Don t use email to distribute encryption keys Even if you re not sending emails in plain text an intruder who has stolen account names and passwords will receive the messages with your new codes before your legitimate users get them If it s practical to do so on your network turn on the access control fea ture in your access point Access control restricts network connections to network clients with specified MAC addresses The access point will refuse to associate with any network device whose address is not on the list This might not be practical if you want to allow visitors to use your network but it s a useful tool in a home or small business network where you know all of your potential users MAC address filtering will not pre vent a determined attacker from copying and spoofing the address of an authenticated user but it could provide an additional layer of protection Turn on the security features but treat the network as if it s completely open to public access Make sure everybody using the network under stands that they re using a no
195. furniture and other objects between the two antennas can all reduce the signal strength 802 11b networks were the first to appear and they were the most common type until the faster 802 11g version became available 802 11a uses different radio frequencies but many network adapters are compatible with both 2 4 GHz and 5 2 GHz access points Today the new 802 11n standard is beginning to replace all three older versions The three systems that use channels in the 2 4 GHz frequency band are backward compatible In other words if your Wi Fi network interface adapter uses 802 11b only it will continue to work with an 802 11g or 802 11n base station both 802 11b and 802 11g adapters will work with an 802 11n base station The missing letters 802 11c d e and so forth describe other wireless data charac teristics and enhancements that apply to wireless data networks They re important to hardware designers and manufacturers but as a network manager or user you don t have to worry about them You might also see some Wi Fi access points and network adapters identified as extreme or enhanced or with some other word which suggests that they work at faster speeds than a standard network Most often these systems use a proprietary method that involves two or more parallel channels to increase their data handling capacity Enhanced systems usually work as advertised but only when the adapter and access point were both made by the same comp
196. g it s inevitable that something you need on this computer is stored on or connected to that computer The solution to this problem is easy Simply connect the computers and allow them to share Congratulations You have just created a computer network Two or more computers connected through wires radio signals flashing lights or any combination of those and other methods form a network that you can use to send and receive instructions and files from one computer to another Whether you re using your computers at home at school in a small business or even at a temporary gathering such as a business conference or a camping trip if you re the sort of person who takes computers along on a camping trip connecting them through a network makes every one of them more useful and more powerful And when you connect your network to the Internet every device on your local network also becomes connected to the Internet When you connect two or more computers in a network each computer becomes more useful There s a rule that describes this called Metcalfe s Law Robert Metcalfe was the original designer of the Ethernet structure used in most modern computer networks his law states that the value or power of a network increases in proportion to the square of the number of devices connected to that network The math is pretty subjective but Metcalfe s Law says that two computers connected together are about 4 times as useful as a singl
197. g for considerably less money if we re willing to use a computer instead Audio File Formats Digital music players convert sound and music files in common formats to analog sounds that you can play through headphones or speakers Some of these formats use compressed audio that squeezes the data into smaller files Others use larger uncompressed files that maintain all the original details The most common format for compressed audio files is MP3 The most widely used formats for uncompressed files include WAV and AIFF Table 15 1 lists the formats that you re most likely to see The choice of format is a trade off between the size of the file and the quality of the sound As a rule of thumb sound quality increases with file size as measured in bits per second A WAV file of a music track might require eight to ten times as much storage space as an MP3 file of the same recording but the WAV file is almost always a more accurate copy of the original The compressed MP3 file occupies less space on a hard drive and can travel across the network more quickly but the added bits in the WAV file will mean that the music has less distortion and better frequency response the range between the lowest bass notes and the highest treble tones In other words an MP3 file might sound like the recording played through an AM radio whereas the same music played from a WAV file could sound at least as good as a very good CD player Other Things You Can Co
198. g for the source of a problem in the most logical device If you have a hardware problem it s often effective to isolate the problem by replacing individual components and cables one at a time until the problem goes away If the problem disappears when you install a replacement that s a good indication that the original part was the source of the problem If the replacement is a relatively expensive item like a router or a printer you might want to send it back to the manufacturer for replacement or repair especially if it s under warranty But if you replace a cheap part like a cable or a network interface card it s often easier to just throw it away and buy a new one Similar techniques can work with software If a computer connection fails try shutting down each program running on that computer one ata time and then try to reestablish the connection If you recently installed a new program driver or update try uninstalling the new software and test the connection again If the connection works the conflict is between the new software and your network connection or device driver In Windows try restarting the computer in Safe Mode and re establishing the connection if it works in Safe Mode you know that the Windows operating system is not the source of the problem Retrace Your Steps Even if a network problem appears without warning the problem was probably caused by something that has changed within the hardware or softwar
199. gital video files on the TV screen In rooms with both a computer and a large screen TV it s often worth the trouble to connect the TV directly to the computer as a complement to the smaller computer monitor The quality of pictures and text on a TV screen is not always as sharp as the same images on a computer monitor an image from a broadcast or cable TV signal or a DVD player but with a bit of tweaking it can be good enough to watch Connecting Directly to a Computer To connect a TV directly to a computer you need two things e An output signal from the computer that s compatible with an input to the television e Driver software for the computer s video controller Your television has one or more of these input types e Two or more screw terminals that connect to a flat antenna cable e Athreaded socket that mates with a coaxial cable from an antenna cable TV service or other program source the socket and mating plug at the end of the cable are called F connectors e Acircular connector with either four or seven sockets that mates with a matching multipin plug called an S Video for Super Video or Separated Video plug e Three color coded sockets yellow for video white for stereo audio left or mono and red for stereo audio right for analog audio video cables these are similar to the RCA phono plugs and sockets used in most home stereo systems e A15 pin analog VGA connector like the one used by older computer display m
200. gnal deteriorates due to interference or fading the client will try to shift to another access point on what it thinks is the same network This transfer is called a handoff If two different networks with overlapping signals have the same name a client will assume that they re both part of a single network and it might try to perform a handoff from one network to the other From the user s point of view this misdirected handoff will look like the network has completely dropped its connection Therefore every wireless network that could possibly overlap with another network must have a unique SSID The exceptions to the unique SSID rule are public and community net works that only provide access to the Internet but not to other computers or other devices on a LAN Those networks often have a common SSID so subscribers can detect and connect to them from more than one location In other words if you have an Internet access account at your local coffee shop you might find and use exactly the same SSID when you visit another shop owned by the same company Network Security 177 178 WARNING Chapter 13 A network s SSID provides a very limited form of access control because it s necessary to specify the SSID when you set up a wireless connection The SSID option in an access point is always a text field that will accept any name you care to assign but many network configuration programs including the wireless network tools in Wi
201. h as compact discs e Broadcast radio stations e Cable and satellite radio stations or music services e The Internet e Digital music files stored on a computer s hard drive or a portable device such as an iPod 4 Destination Figure 15 2 The source of the music played on this gramophone is the needle on a grooved shellac disc the destination is the horn The destination can be any of the following e Speakers connected to a home stereo system TV receiver or surround sound system e Speakers connected to a computer or built into a laptop e Headphones or a docking unit s speakers connected to a portable device such as an iPod e Astorage device such as a hard drive or a flash drive e A tabletop or portable boom box or Internet radio A home network can connect any of these sources to any destination It might be necessary to convert the source from analog to digital format before it moves through the network and you might have to convert the digital data back to analog before you play the sound through a speaker or headphones but these are relatively minor technical details the important point is the same network that handles other data can also distribute digital audio files In networking terms you can think of the devices that handle program sources as servers and the destinations as clients Audio Servers An audio serverin a home network stores music radio programs and other sound files that are accessible to
202. h can provide you can connect one or more additional switches to one of the ports on the original unit Photo courtesy of Linksys a division of Cisco Systems Inc Figure 3 4 This switch connects five network nodes Networks in larger business offices usually run cables from each computer back to a central space where all the switching equipment is mounted ona wall plate or an equipment rack This is often the same room where in house telephone equipment connects to the telephone company s outside lines This space is often called a wiring closet LANs and WANs The network in your home or office is known as a local area network LAN All of the computers connected to a LAN can share peripheral devices such as a printer or a scanner they can run programs and read data from other computers on the same LAN and they all share a common connection to the Internet In a home network the LAN might also include home entertainment systems and game controllers A LAN also uses the same set of rules and settings to control communi cation among all the networked computers These include the name of the network itself and names or address numbers or both for each computer and sometimes firewalls that protect the privacy of the people using the LAN When you want to connect several LANs you can create a network of networks called a wide area network WAN that can use communications channels such as telephone lines or a cable TV se
203. hat makes it easy to figure out where the signal is coming from e Don t use an SSID that makes your network sound as though it contains some kind of fascinating or valuable content use a boring name like say network or even a string of gibberish such as W24rnQ If a would be cracker sees a list of nearby networks yours should appear to be the least interesting of the lot e Change your access point s password The factory default passwords for most access point configuration tools are easy to find and they re often the same from one manufacturer to another hint don t use admin so they re not even good enough to keep out your own users let alone unknown intruders who want to use your network for their own benefit An unauthorized person who could be one of your own children who gets into the access point s software could lock you out of your own net work by changing the password and the encryption key If possible place your indoor access point in the middle of the building rather than close to a window This will reduce the distance that your network signals will extend beyond your own walls Use WPA encryption rather than WEP WPA encryption is a lot more difficult to break especially if it uses a complex encryption key Change your encryption keys often It takes time to sniff encryption keys out of a data stream every time the keys change the miscreants trying to steal your data are forced to start again
204. he operating system will load the device driver software right away In some less user friendly Unix or Linux distributions it might be necessary to compile the kernel to support a specific network driver and load the module at runtime but this is not common However if you re working with an older operating system or a network interface that the operating system can t recognize you ll have to find and install the correct device driver A device driver is a small program that converts between the generic output signals supplied by the computer s central pro cessor and the specific instructions that control the features and functions of a device connected to the computer It also converts incoming commands and data from the peripheral device to a format that the central processor can recognize New network adapters usually come with a software disc that contains the device driver and other related programs and documentation If yours is missing or if the disc doesn t contain the right driver for your operating sys tem you can probably find a driver program on the adapter manufacturer s website or through an online source of open source device drivers Several websites offer direct links to hundreds of sources for device drivers http www windrivers com http www pcdrivers com hitp www driverzone com hitp www driverguide com hitp www helpdrivers com hitp www winguides com drivers hitp www driversplanet com h
205. he owner of that address is not necessarily located in that country For example many American FM radio stations have obtained addresses in the fm domain which belongs to the Federated States of Micronesia and some television stations use the tv domain assigned to the Pacific island nation of Tuvalu Table 4 1 lists the most common generic top level domains Table 4 1 Generic Top Level Domains Top Level Domain Used By com Originally commercial but now a generic domain net Originally reserved for domains related to networks but now a generic domain edu Reserved for US colleges and universities org Originally reserved for nonprofit organizations but now a generic domain gov Originally reserved for the US government but now also used by state and local governments mil Reserved for branches of the US military info A generic domain with no restrictions biz A generic domain restricted to businesses name A generic domain reserved for individuals Some other top level domains such as asia coop museum and travel are restricted to certain categories of users Still others such as Jui HCIIBITaHHe OOKILLN Jeles are for addresses that don t use the Roman alphabet Name Servers DNS name servers are an essential part of the Internet s internal plumbing but most people don t know that they exist If your computer can t find a DNS server your email program web browser and other Internet programs won
206. he sizing icon on the Remote Desktop tab at the top of the screen This will allow you to copy text data or files between the two computers To return control to the local user click the X on the control tab near the top of the screen NOTE fyou try to use an account without a password to take over a Remote Desktop connec lion you will get this error message Unable to log you on because of an account restriction Jf you see this message go to Control Panel User Accounts on the target computer select Change an account to assign a password to your account and then try connecting again Virtual Network Computing VNC Virtual Network Computing VNC is a system that allows one computer the client to gain remote access to a second computer the server and to use the first computer s mouse and keyboard to control the second computer In general VNC is not as fast as the Windows and Macintosh remote desktop programs but it s more flexible Unlike the Microsoft tools described in the previous section VNC is not limited to any operating system you can use any VNC client or viewer to control any VNC server even if the two computers use different operating systems Several VNC based programs are available that offer clients and servers for more than one operating system including RealVNC Attp www realunc com UltraVNC hitp www uvnc com and TightVNC http www tightunc com Several others are limited to Linux and Unix
207. hen you want to transfer data from one computer to another when one or both of them are not already connected to a network For example if you re in a meeting where some body asks for a copy of a report or drawing you could use the built in infrared network tools built into many laptop computers to shoot the file across the table from your computer to your colleague s Or if you want to copy a file from a friend s computer you could plug a transfer cable into both machines or set up a point to point Wi Fi link Types of Network Connections 19 20 Chapter 2 Desktop MacBook computer Laptop Desktop computer computer Desktop Laptop computer computer Figure 2 7 A LAN left can provide connections between any pair of nodes a point to point network right connects two nodes Point to point networks can use wires radio signals or infrared light to exchange data between the two endpoints If you re using a cable connection you must use a special point to point Ethernet adapter or cable For a point to point Wi Fi link you must configure it as an ad hoc connection Ad Hoc Wi Fi Most Wi Fi networks connect wireless nodes to a LAN through a wireless access point but Wi Fi network adapters can also support wireless links directly from one computer to another This kind of connection is called an ad hoc network because it s usually set up as a temporary link rather than as part of a permanent network infrastruc
208. home appliances 8 222 228 home automation 8 49 51 223 home entertainment systems 7 8 48 49 203 206 Home Phoneline Networking Alliance 17 HomePlug 17 17 HomePNA 17 home run wiring 51 52 52 53 home security devices 8 205 hosting services 105 host names 43 Hotmail 105 hotspots 77 78 89 HOWTO 159 164 HP Hewlett Packard 95 HTTP See HyperText Transfer Protocol HTTP hubs data 30 55 designing 47 Ethernet 29 29 80 220 network 120 overview of 28 30 29 111 for printers 193 201 hybrid wireless networks 89 HyperTerminal programs 22 HyperText Transfer Protocol HTTP 24 39 web servers 158 IANA Internet Assigned Name Authority 37 38 157 IBM 82 94 iChat 237 IDE hard drives 97 IEEE Institute of Electrical and Elec tronics Engineers 21 78 ifconfig 43 IM instant messaging 7 233 237 incremental backups 100 indicator lights 75 individual bits 10 70 industrial electronics suppliers 57 info 40 Infrared Data Association IrDA 20 ports 20 21 21 infrared networks 20 21 21 input output I O ports 4 18 18 19 19 instant messaging IM 7 233 237 Institute of Electrical and Electronics Engineers IEEE 21 78 Intel 88 164 internal controllers 204 205 internal expansion cards 72 72 73 Internet Assigned Name Authority IANA 37 38 157 Internet based IM services 234 235 Internet connections network 110 115 111 112 Internet Explo
209. hosting 45 Layer Two Tunneling Protocol L2TP 162 163 164 169 LED indicator lights 240 242 243 Level 1 5 access 133 136 Leviton 67 LG Electronics 223 limited backups 100 line of sight 85 LINK indicator lights 75 Linksys 216 Linux backup files 100 104 computer to network connections 117 127 127 129 128 129 CUPS printer control program 199 file servers 94 95 96 215 file sharing 131 147 150 148 150 firewalls 154 159 155 158 164 network adapters 73 74 network to Internet connections 115 OpenVPN for 173 remote desktop programs 229 text commands for 43 troubleshooting info 247 VPN clients for 172 173 VPN servers for 164 wireless control programs 87 LinuxCD 95 Linux Online 104 live conversations 205 233 237 Living Network Control Protocol LnCP 223 local area connections 42 42 122 123 196 local area networks LANs addresses 37 38 computer to network connections 117 123 connections to 20 21 32 41 49 55 data transfer speeds 14 15 Ethernet 14 16 71 file sharing 137 firewalls 154 159 155 158 game consoles 220 222 instant messaging 234 236 235 network to Internet connections 107 115 108 111 112 overview of 31 32 32 remote terminals 23 23 security methods for 91 92 troubleshooting for 248 251 VideoLAN 218 VPNs and 159 161 160 161 163 Wi Fi and 54 77 78 wireless security 54 89 92 174 184 175 178 181 LostPC 185 LPs music
210. i networks are also filled with signals from cordless telephones medical equipment radio controlled toys and microwave ovens among many other things Wi Fi and those other devices use different methods to transmit and receive radio signals so there s not much danger that the Wi Fi adapter in your laptop computer will cause a model train wreck or cause your cordless phone to ring However other ISM or U NII signals along with Wi Fi signals from other nearby users can add noise to your Wi Fi signal that reduces the network s data transfer speed Within the 2 4 GHz band there are 14 overlapping Wi Fi radio channels Japan is the only major country that uses all of them Only 11 of those channels are used in North America and China while most of Europe uses 13 channels In France only 4 channels are available Each channel operates on a different frequency numbered from Channel 1 to Channel 14 Each channel overlaps the two channels above it and two below it as shown in Figure 8 1 so the channels with adjacent numbers can interfere with one another Like the interference from other ISM devices adjacent channel interference can create a slower noisier connection Therefore when you re setting up a new network or adding an access point to an existing network it s best to choose a channel number as far away from the channels used by nearby networks as possible Wi Fi Networks 79 80 22 MHz channel SS l l l l 2
211. ial part of the culture others hardly use it at all For an extensive study of instant messaging and the way people in business use it take a look at Interaction and Outeraction Instant Messaging in Action Proceedings of Conference on Computer Supported Cooperative Work 79 88 New York ACM Press hitp dis shef ac uk stevewhittaker outeraction_cscw2000 pdf The authors of this study offer some interesting insights but they have buried them under some seriously dense academic language using highfalutin words like dyadic and ethnomethodology Just about every messaging program has a similar structure It displays a list of other users with an indicator that shows whether each user is currently available to receive a message Users might not be available because their messaging program is not active or because they have set the program to not accept incoming messages To start a conversation click the intended recipient s name When a message arrives it appears in a pop up window on the recipient s screen some programs also sound an audible signal when they receive a new message Other Network Applications 233 234 NOTE Chapter 16 Instant messaging is not the same as online chat but the experience is similar The difference is that chat takes place among two or more participants who connect to a common channel a chatroom When you join a chat you instruct the program to connect to a specific chatroom Instant messaging
212. icular problem they have probably included instructions for fixing it in the Knowledge Base Similar resources exist for Macintosh networks and servers at hitp www apple com support and for Unix and Linux systems in the Support sections of each distribution s website Other online sources for useful troubleshooting information include manufacturers technical support centers independent newsgroups and web forums and sites such as Wikipedia and HowStuffWorks com that offer descriptions and explanations of various types of technology If those sites don t answer your question try a more general web search Type a few keywords that describe the problem such as XP can t find network printer or the exact text of an error message into a web search tool and follow each of the links to read about other people s experiences under similar circum stances Remember that quotation marks around phrases instruct the search sites to search for the entire phrase rather than individual words One particularly helpful tool for troubleshooting networks is the Windows Network Problem Solver at hitp winhlp com wxnet him shown in Figure 17 1 The Problem Solver is an interactive list of symptoms that links to instructions for solving the most likely cause of the problem If you take the time to carefully answer each of the questions in the problem definition form the Problem Solver can be a remarkably effective tool Troubleshooting 247 248 indows
213. ient sends audio to an amplifier s analog or digital auxiliary input Dedicated Music Client Devices As an alternative to using a computer consider using a separate device speci fically designed as a music client or network music player The client device sends an instruction to find and play a specific music file or other audio track to the music server which streams the requested file back to the player The player can either send the digital stream to a converter in the audio system or convert the file to an analog signal and send the music signal to the audio system For example Slim Devices makes a family of Squeezebox music clients including the Squeezebox Classic Squeezebox Receiver and Squeezebox Transporter Figure 15 5 shows the connections on a Squeezebox for a net work and a stereo system Similar products are available from Roku Netgear Philips and other companies Most of these devices are marketed as audio components so the best place to look for a demonstration is probably a home audio retailer rather than a computer store Each music client manufacturer supports a different set of audio file formats they all work with the most widely used formats but if your library includes more obscure formats you should confirm that a client can recog nize them Network music players offer several benefits They occupy less space than a computer they re often easier to use and they can provide sound quality as good as or bet
214. ific number of packets Because WPA changes the key frequently it s a lot more difficult for a cracker to gather enough information to decipher its encryption code In large networks WPA uses an authentication server to verify the identity of each network user The server uses Remote Authentication Dial in User Service RADIUS and Extensible Authentication Protocol EAP to exchange encryption keys with the computers and other devices that are connected to the wireless network In home networks and smaller business networks that don t have a server a method called pre shared key PSK mode uses a passphrase stored in the access point in place of the authentication server To connect to the network users must enter the same passphrase on their computer or other network device or set their device to automatically enter the passphrase When you set up WPA encryption you must specify whether the network uses a server or PSK mode Any access point and network adapter that supports 802 11g or 802 11n should also recognize WPA encryption If you re using an older 802 11b or 802 11a access point you might be able to add WPA encryption by installing the latest version of firmware and drivers Look in the support or downloads section of the manufacturer s website for free upgrade instructions and software PSK Passphrases A WPA PSK passphrase can be a string of either 8 to 63 ASCII characters or 64 hexadecimal digits The passphrase that y
215. ind a network node or any of a truly amazing number of other possible problems occurs as the local network expert it s your job is to fix it Network problems always have a specific cause or combination of causes even if that cause is not obvious Too often a network error message will say something like ask your network manager for assistance But when the network manager is you that message doesn t tell you how to solve the problem This chapter offers some tools and methods that will help you identify and solve most network problems 240 General Troubleshooting Techniques Chapter 17 The key to successful troubleshooting is to follow a logical problem solving process rather than simply trying things at random until you stumble upon the correct solution to your problem Most people who spend a lot of their time fixing things use a system like this without a formal plan but if you re new to repairing computers and networks consider using the techniques in this chapter as a guide Many of these suggestions are common sense answers rather than complex technical procedures Don t overlook them otherwise you can spend hours tracing a circuit or trying to find a bad connection just because somebody has unplugged a cable Remember that a problem that appears in your network might really be located on one of the computers or other devices connected to the network In many cases you will want to look for problems in th
216. ing errors or unclear descriptions are my own responsibility Thanks also to Jim Cavin for allowing me to connect his MacBook to my network and Tommy Tse for his assistance in obtaining evaluation software from Microsoft And thanks as usual to my agent Carole McClendon who started the wheels turning on this project INTRODUCTION This book is for people who never expected to build or run a computer network You were happily using a computer sending and receiving email writing reports and maybe down loading music through the Internet when one day you looked around to discover that one computer had somehow multiplied now you have two or three or more computers Maybe each of your children needs his or her own computer to do homework or all of your employees have computers on their desks Or maybe you brought a portable laptop computer home from work and you want to use it along with the family s desktop machine Whatever the reason you now have several computers and you need a way to connect all of them to the Internet at the same time and to share files printers and other resources among them You need a network xvi Introduction A network Yikes Isn t a network some kind of invisible monster that requires expensive equipment and people to keep it running who speak a mysterious language and go off to seminars with titles like The Power of Virtualization or Removing Internet Anonymity Barriers with IP Inte
217. ing principles involved in network file sharing you shouldn t have any trouble working with a mixed network In this section I m describing tools for sharing files that are part of the most commonly used Linux and Unix desktop environments Gnome and KDE If you re a hardcore user who works from the command line rather than a desktop I m assuming you already know how to create and use network shares or if not that you can find specific instructions from man pages and other documentation Sharing from Linux or Unix Computers Both of the major Linux Unix desktop environments Gnome and KDE include relatively easy to use network file browsers In Gnome the program is called Nautilus as shown in Figure 12 15 To open the network file browser go to the Places menu on the Gnome desktop and select Network Sharing Files Through Your Network 147 fen Windows shares on local File Browser Xe x File Edit View Go Bookmarks Help e X m t Back Forwar Jp Stor Search B 5 windows shares on local Q 100 Q Places v B E ubuntu ei DESKTOP La File System 8 4 GB Media I2 7 9 GB Media Network Servers G Trash E Documents E Music ea Pictures E Videos Figure 12 15 Gnome s Nautilus file browser includes access to network shares In KDE the comparable function is part of the Konqueror file manager as shown in Figure 12 16 smb local Konqueror Location Edit View Go Bo
218. ing a network as part of a major remodeling or new construction plan to coordinate your efforts with the contractors or outside installers who will provide electrical wiring telephones cable or satellite TV and wiring for a home theater or home entertainment system With all this information in one place it s easy to decide where you will want to install network connection points Use yet another color of pencil to mark an unobstructed place for the network outlet on the wall nearest to each computer and every other device you plan to connect to the network Each outlet should be at least a foot from the closest electrical outlet both because AC wiring can generate interference that affects data signals and because it s often required by the local electric code to prevent shorting between AC and data cables If your telephone or cable TV outlets are mounted on wall plates rather than in small boxes attached to the baseboard consider replacing the existing wall plate with a new one that combines two or three outlets of different types on a single wall plate as shown in Figure 5 2 When you design your network you should also plan for the future You probably don t need them today but within a few years it s quite possible that you will want to connect your household appliances a bedside radio and other devices to your LAN and the Internet And if you plan to eventually add one or Figure 5 2 This wall plate more online ca
219. ing document e Transmit them through the computer s network connection The alternative to a camera connected to a networked computer is a network webcam a camera and control unit that connects directly to the net work as a separate node A typical network webcam includes a remote control program on a web page that a user can operate through the network or with the correct set of passwords and authorization through the Internet Depending on each camera unit s specific features the remote control might allow an operator to zoom the image in and out rotate or tilt the camera or choose a different image through the same control unit Some network webcams also include a wireless network interface that can connect to the network through a Wi Fi base station Networked Cameras and Microphones Attaching a camera to your network with or without a microphone at the same location can add many useful features and functions Anyplace where you want or need a distant set of eyes and ears you can install a camera a microphone or both Here are some examples Surveillance monitors One or more cameras aimed at unattended entryways corridors and other locations can transmit pictures to a dis tant computer s video display monitor Baby monitors A networked computer with a camera and microphone in a nursery or child s room can replace a conventional baby monitor transmitter unit You can keep an eye on the baby while you work through
220. ings and close the Properties window Using Remote Desktop To take control of another computer using Remote Desktop in Windows XP or Remote Assistance in Windows Vista follow these steps l Select Start gt All Programs Accessories Remote Desktop Connection A dialog similar to the one shown in Figure 16 3 will appear Remote Desktop Connection amp es Mu Remote Desktop lt i Connection Compute ZE Username DESKTOP Wohn Ross You will be asked for credenbals when you connect Lone Figure 16 3 Use the Remote Desktop Connection dialog to specify the computer you want to control Type the name of the computer you want to control and click Connect Your screen will go black except for a control tab near the top of the screen and a Log On box 3 Type a valid account name and password for the target computer in the Log On box and click OK The screen on the distant computer will go dark and you will see an image of the distant computer s desktop on your screen You can now control the distant system with your own computer s keyboard and mouse You can open files run tests and load programs though the network However a user looking at the distant computer s screen will see nothing but a dark screen When a new Remote Desktop connection opens it fills the client computer s screen but you can reduce the size of the Remote Desktop window and see your own computer s desktop and Start menu by clicking t
221. intentional or accidental misuse or abuse by internal network users Computer networks are vulnerable to several forms of attack including unauthorized access to files theft of service and denial of service caused by excessive network connection requests Strictly speaking attacks on individual computers such as viruses worms and Trojan horses are a separate issue from network vulnerabilities but a good network security plan will include firewalls and other tools that also protect the computers connected to the network This chapter describes the basic steps that every home and small business network manager must take to keep his or her network secure 152 Keeping Intruders Out Chapter 13 Intruders break into networks for several reasons e They want to open files and read documents either to steal confidential information or just to overcome the challenge of cracking protected files e They want to use the network to obtain a high speed Internet connection e They want to use the network to forward unsavory or illegal data such as spam or pornography to the Internet or download similar material e They want to steal passwords credit card numbers bank account infor mation and other forms of data that they can either sell or use to order items of value e They want to interfere with normal network operation by overloading the network s ability to handle data altering or deleting essential soft ware o
222. ion make sure your network is protected with a firewall if the network includes one or more Wi Fi access points be sure to use WPA encryption On the other hand don t let these security concerns scare you away from using Level 5 access when it s appropriate In a business where two or more people work together on the same project you will want to allow those involved to create or make changes to the relevant documents On a home network you may want to provide universal access to music photos and video files and documents such as school term papers that a parent might want to review before they re turned in And if you share files between your home or office computer and a laptop you will want to allow Level 5 access between the two To assign the contents of a drive or folder to Level 5 follow these steps 1 From My Computer right click the icon of the drive or folder you want to assign to Level 5 A pop up menu will appear 2 Select Sharing and Security from the pop up menu A Properties window will appear with the Sharing tab visible This window is the same one you used to assign files or folders to Level 4 Figure 12 3 3 In the Network Sharing and Security section of the Properties window check the Share this folder on the network option Check the Allow network users to change my files checkbox 5 Click OK to save your changes and close the Properties window File Sharing in Windows Vista Chapter 12 Micr
223. is computer connects to the Internet directly or through a network hub option and click Next The Wizard will ask for a brief description and a name for this computer as shown in Figure 11 4 Network Setup Wizard I Give this compuler a descriplion and name E Computer description Sam s Office Examples Family Room Computer or Monica s Computer Computer name SAM Examples FAMILY or MONICA The current computer name is TOWER Learn more about computer names and descriptions emen Figure 11 4 Assign a unique name and description to each computer on your LAN Type a brief description of this computer and the name you want to use to identify this computer on the LAN Other users will use this name to connect to this computer through the LAN Click Next The Wizard will ask for a workgroup name Type the workgroup name and click Next You must use the same workgroup name for every com puter on the LAN The Wizard will ask about file and printer sharing as shown in Figure 11 5 If you want to allow other network users to use the printer or printers connected to this computer or if you want to share files stored on this computer with other network users select the Turn on file and printer sharing radio button if you do not have a printer connected to this computer or you don t want other users to use the printer and you don t want to share files select the Turn off file and printer sharing radio button If you do
224. itp www totallydrivers com Status Lights on Network Adapters Most Ethernet adapters have two or three status indicators that light and go dark as data moves through the network connection On an expansion card the lights are usually on the metal mounting bracket just above or below the RJ 45 connector on a PC card they might be on the card itself or on the socket that connects to the network cable Indicator lights on a built in Ethernet socket are usually right next to the socket itself The three indicator lights are LINK Lights in green when the adapter is connected to a live network 10 100 Lights in yellow when the adapter is connected to a 100 Mbps network goes dark when it s connected to a 10 Mbps network ACT Flashes in green as data passes through the network connection in either direction These lights are useful for troubleshooting and watching network per formance because they can tell you whether your network connection is working properly For example when the LINK indicator lights you know that the computer is connected to a live network when it s dark the network connection is offline When the ACT light flashes it tells you that the com puter is sending or receiving data Unfortunately the lights are often located in a place where it s difficult or impossible to see them while you re using the computer When you re testing the system it s often helpful to ask someone else to watch the lights while you ope
225. l The alternative is to send your message to a switching center that will hold it until a link to the destination becomes available This is known as a store and forward system If the network has been properly designed for the type of data and the amount of traffic in the system the waiting time will be insignificant If the communications network covers a lot of territory you can forward the message to one or more intermediate switching centers before it reaches the ultimate destination To make the network even more efficient you can divide messages that are longer than some arbitrary limit into separate pieces called packets or frames Packets from more than one message can alternate with packets containing other messages as they travel between switching centers and reassemble themselves into the original messages at the destination The great advantage of this approach is that many messages can share the same circuits on an as available basis The packets from a single message might alternate with packets from one or more other messages as they move through parts of the network For example if you send a message to a recip ient in another city the packets usually move through an inter city channel along with many other messages Each data packet must also contain yet another set of information the address of the packet s destination the sequence order of this packet relative to other packets in the original transmission and so forth
226. l allow them to let you know when the roast is cooked or the clothes dryer has completed its fluff cycle Chapter 15 provides basic information about home automation systems and devices and explains how to connect them to a computer network TYPES OF NETWORK CONNECTIONS must follow a set of rules and specifications that define the characteristics of both the physical connection and the form and structure of the data that moves from one computer to another Without these rules the people using the network cannot be sure that their computers will communicate successfully For example the plugs at the ends of data cables must match the sockets on each computer and other network hardware If a cable uses a square plug with two pins but the computer has a round socket with four holes they won t fit together The same thing applies to the electrical voltages timing error checking and other issues There are many different kinds of networks each with its own rules This chapter explains a few general principles about networks and describes the network types that you re most likely to see ina home or small office network 10 Chapter 2 You can use a network without understanding all the internal details of network communications but if you re designing and building a new network you should know how to choose the best options for your particular require ments You can treat individual network components as a series of black boxe
227. l center and place the modem router and switch near the computer but remember to allow for addi tional network nodes in the future A single wall plate can hold up to six data outlets so it s possible to run cables to several other rooms without installing an industrial looking row of mounting blocks A data outlet block is the transition between internal data wiring inside a wall and a socket for a cable with Ethernet plugs at each end Terminating each cable from another room with an outlet will make it easier to make additions and changes to your network wiring Installing the Network Control Center and Ethernet Cables 59 One side of an outlet block has a set of slotted pins that each holds one of the wires inside a data cable and the other side has a socket for an Ethernet plug A data outlet can be located on the side of a small box attached to a base board or to the plywood base of your control center or ona flush mounted wall plate Figure 6 2 shows an outlet block with cables connected to both sides The cover has been removed to make the individual wire connections visible Figure 6 2 An outlet block provides a transition A completed control from loose wires to an Ethernet connector center on a plywood panel will look something like Figure 6 3 Network Telephone terminal ine blocks To other rooms Phone line terminal block Figure 6 3 A homebrew control panel should include connections for AC power
228. l in one device almost always costs less and occupies less space than a separate printer scanner copier and fax machine however the large number of features and functions often means that it s more difficult to operate than a simple single function device Printers and Other Devices on Your Network 199 Figure 14 7 is a functional flow chart that shows the types of sources and destinations that an all in one device can handle The device can receive an image from a computer or through a telephone line or it can create a digital copy of a physical image such as a printed page a transparency or a small object placed on the surface of a scanner The device can send the digital image to any of several different destinations a printer a computer file or a distant fax machine If your all in one device also includes a network interface you can use it to accept print jobs or outgoing faxes through an Ethernet network and you can send scanned images and incoming faxes to any of the computers connected to the same network Some all in ones can also send images through the Internet as email attachments 3 Q Scanned Computer image file A X Fax via All in one Printed telephone line device page QA I Computer Fax via file telephone line Figure 1 4 7 An all in one device can obtain images from different sources and send them to any of several destinations Each of the all in one s activities is a specific combinatio
229. le and the cable s sensitivity to interference Unless you plan to install a super fast Gigabit Ethernet network CAT5e is usually the best compromise between cost and performance in a home or small office network Don t use CAT cable for new installations It might be okay for today s networks but it won t reliably support the next generation of high speed data services Ethernet cables come in two forms bulk cable on spools or in boxes and pre assembled cables with connectors already attached Pre assembled data cables are often called patch cords patch cables or jumper cables They re NOTE available in many colors and in lengths ranging from 1 foot to 100 feet Use different colored patch cords with a switch or any other device that has lots of connections multiple colors will allow you to find the right one quickly Bulk cable is the right choice for runs inside walls between your control center and the data outlets in other rooms On the other hand pre built cables are better for shorter distances such as between terminal blocks or wall outlets and computers control devices and other equipment because they re often made with more durable jackets and plugs that have permanent collars It s possible to build your own patch cords out of bulk cable and loose plugs but attaching plugs to cables is tedious work that s generally more trouble than it s worth As a rule of thumb use bulk cable for permanent installations with
230. le as 8MB of memory The NetBSD 1386 Firewall Project home page is Attp firewall dubbele com Virtual Private Nerworks NOTE A virtual private network VPN can add another effective form of security to data that moves from a remote client to a host network that can be located anywhere with a connection to the Internet A VPN uses a data tunnel to connect two points on a network through an encrypted channel The endpoints can be a single network client and a network server a pair of client computers or other devices or the gateway to a pair of LANs Data that passes through a public network such as the Internet is completely isolated from other network traffic VPNs use login and pass word authentication to restrict access to authorized users they encrypt the data to make it unintelligible to intruders who intercept the data and they use data authentication to maintain the integrity of each data packet and to assure that all data originates with legitimate network clients VPN functions occur at the IP or network layer of the ISO model Therefore they can operate on top of the Wi Fi or other wireless protocols which operate at the physical layer VPNs can also pass data across a network connection that includes more than one physical medium for example a wireless link that passes data onward to a wired Ethernet network In other words a VPN is an end to end service the data can use a wireless link an Ethernet cable an ordinary tel
231. le to every network user while others might be limited to specific users and still others are only available to the file s owner One of the most common network systems for sharing files printers and other resources is the Server Message Block SMB protocol This protocol is at the core of Microsoft Windows networking and it also works with Macintosh OS X and Linux Unix systems Therefore exchanging files among computers that run different operating systems is not a problem even though the files themselves might not always be compatible for example you probably can t run a program written for Windows on a Linux system 132 Many operating systems support more than one networking protocol but when you run a mixed network or if it s remotely possible that a visitor with a different kind of computer such as a Mac or Linux laptop might want to connect to your network it s best to use the most common protocols Control of file sharing rests with the computer that holds each file so other people can t open and read your files without your permission even if they have a login account or they re using a guest account on the same computer In order to share files with other users you must turn on your operating system s file sharing service and then assign an access level universal limited or none to each folder or directory This chapter explains how to set up file sharing in Windows XP and Vista Macintosh OS X and in
232. lephone wall outlets and connection boxes If you plan to use a DSL or dial up connection to the Internet your network will use telephone outlets to connect Cable TV or other video outlets Ifyou get your Internet service from your cable TV provider you will connect a modem to a cable outlet Even if you don t use cable Internet service you might want to use com bined wall plates for video and data outlets 48 Chapter 5 Furniture placed next to a wall You won t want to plan a network outlet socket in a place that forces you to move a bookcase or a sofa to get to it On the other hand if there s a table against the wall you could probably crawl underneath easily to plug in a cable in a place where it won t call attention to itself Closets stairways and other hiding places If your home or workplace includes spaces on more than one floor of the building be sure to note the locations of closets stairways and other places where it will be rela tively easy to run hidden cables through ceilings or floors As with the other wiring in your home or workplace your goal will be to hide all your network cables inside walls under floors and in other invisible locations If you re adding the network in an existing home or office all of these elements are probably in place already Before you start to add new network wiring and connection points you must understand how they will relate to the other things in each room If you re plann
233. les from an entertainment server to speakers and video displays in several locations around your home This chapter explains how to connect and use additional devices with your network 204 Using a Microphone and Camera with Your Network NOTE Chapter 15 A microphone connected to a computer or audio server can capture sounds and convert them into digital audio files A camera known as a webcam can capture images that a computer or server can convert to still or moving image files An audio or video server can be either a computer with an internal or external microphone or a camera or both or a stand alone device that connects directly to the network When another computer receives the same audio and or video files through a network it can display the images on a display monitor and play the sounds through one or more speakers or through a pair of headphones One widely used remote webcam service is the familiar online traffic monitor like the one shown in Figure 15 1 Figure 15 1 A traffic webcam uses a networked camera This one shows cars and pedestrians on the Brooklyn Bridge Internal and External Controllers A video camera can connect to a network through a controller mounted inside a computer on a plug in PCI expansion card or as an external USB device The controller scans the light sensitive portion of the camera from side to side and from top to bottom at a constant rate when it reaches the end of one row the cont
234. level 39 41 40 Domain Name System DNS 39 41 42 44 109 158 servers 40 41 42 43 44 109 115 118 124 127 246 DoS denial of service attacks 189 dot 39 downstream switches 67 drive by logins 174 drivers device 74 75 DSL connections 6 22 32 62 64 99 modems 110 DTE data terminal equipment 18 19 DVI digital visual interface 218 219 231 DVI to DVI cables 219 DVI to HDMI cables 219 220 DVR digital video recorder 216 217 Dynamic Host Configuration Protocol DHCP 37 38 42 43 86 109 115 246 servers 38 109 115 111 112 117 118 124 126 126 129 157 158 163 dynamic IP addresses 37 38 86 109 EAP Extensible Authentication Protocol 182 Edirol 211 edu 39 40 Elcomsoft Distributed Password Recovery 183 electrical outlets 48 50 49 52 52 55 56 59 electronics suppliers 57 email services 105 E Mu 211 encryption methods 54 89 91 159 ASCII keys 180 181 end to end 89 159 hex keys 180 181 181 WEP 90 91 174 175 176 179 182 181 183 217 wireless security and 174 184 175 178 181 WPA 54 78 90 91 136 160 174 176 179 181 182 183 194 217 WPA2 90 176 enhanced systems 78 79 equipment data communication 18 19 error checking 9 13 error messages 229 239 240 241 247 ESET Online Scanner 245 ESSID 177 179 Ethernet cables 15 47 53 56 60 60 66 66 77 192 hubs 29 29 80 220 LANs 14 16 71 networks 14 16
235. lgorithm was known to have weaknesses in certain applications all users had to know the key and no secure mechanisms for distributing new keys existed Most of these shortcomings were acknowledged and dismissed as being outside the scope of providing the same protection that a user on a standard wired net work would receive but in fact they meant that wireless equivalent privacy was little better than no protection at all Recent attacks such as those performed by the aircrack ptw tool have further undermined WEP because these tools have often been able to disclose an encryption key in a matter of minutes by analyzing a limited amount of traffic With these developments WEP should be treated more as a do not disturb sign than as a real means of protection The WPA and WPA2 standards attempt to fix the shortcomings of WEP but they only work when all of the users of your network have modern cards and drivers Most if not all network interfaces made in the last few years support WPA or WPA2 For most of us the more serious danger is not that people will eavesdrop on our messages but that they will create their own connection to your network and either read files stored on computers on the LAN or use your broadband connection to the Internet without your knowledge However business networks must take extra precautions to protect their and their customers data Several high profile compromises of customer credit card data in major
236. lligence Not necessarily Networks are not just for geeks any more Today s small networks are relatively easy to install and you don t need an advanced course in computer technology to operate them Even the smallest of small businesses will probably benefit from having a network And home networks are becoming common household utilities just like water electricity and cable TV Like those other utilities you don t need a technical background to use a network This book will tell you what you need to know to build and use a small simple network in your home or business without becoming mired in obscure technical details We thought about calling this book Networks for Nitwits but that s not quite what the book is about you re not a nitwit you re an intelligent com puter user who has been dragged into the world of networks I suggested The Bridges and Routers of Madison County but that would be an entirely different book the bittersweet tale of an Iowa housewife who finds romance with an itinerant network installer Somebody should probably write that book but this isn t it This isa guide to navigating the jungle of servers routers modems and Ethernet cables and to getting the most out of your small network I ll explain how networks operate without getting into too much tedious technical detail describe each part of a network and tell you how to use the net work with computers running Windows XP and Vista Maci
237. lly obtain the settings needed to connect to the LAN and to the Internet When no DHCP server is present or if the DHCP client isn t work ing perfectly you should assign an address manually and enter other settings for each computer individually 118 NOTE You can use a computer with a fixed IP address in a DHCP network but using one is a bad idea because the fixed address can cause collisions with an automatic assignment Some routers and other devices that contain DHCP servers may also allow you to assign a specific IP address to a network node with a particular MAC address The user s manual for your modem or router and the information supplied by your Internet service provider are the definitive sources for network configuration information Make a note of the following settings on your modem or router since you will need them to configure the individual computers e DHCP status on or off e IP address e Subnet mask e Default gateway e DNS servers Connecting Your Windows Computer to a Network Chapter 11 In Windows XP and Windows Vista the Network Setup Wizard creates a profile that connects your computer to a LAN To make changes to an existing profile use the Properties settings for that profile Creating a New Network Profile Follow these steps to run the Network Setup Wizard 1 From the Start Menu select Connect To Show all connections as shown in Figure 11 1 If you re using the Classic Start Menu select
238. m not far from the washer and dryer you probably won t want to connect your appliances to the network right now but remote control and monitoring through your home network is a real possibility in the future In each bedroom plan for an outlet near a desk or table where the room s occupant uses a computer or video game console and if it s not close to the first outlet another outlet for a bedside Internet radio or a laptop computer In an office plan for at least one network connection point next to every desk and every other location where you expect to place a computer or other network device such as a printer If you expect to use both Ethernet and Wi Fi connections to your network note the locations for one or more Wi Fi access point on your floor plan All of your network wiring should use CAT5e or CAT6 data cable less expensive CAT5 no e cable can t handle the higher speed network data that you re likely to need in the future The Control Center The network control center is the location of the switch router modem and other equipment at the core of the network All of the wiring that connects each outlet to the network converges at the control center Common locations for a network control center sometimes known as a wiring closet include closets utility rooms and garages or basements For a very small network no more than five nodes you could also consider placing the modem and router on a table next t
239. mber that the flaws in PPTP networks were identified after that whitepaper was written VPN Servers A VPN server or host can be part of a Linux Unix or Windows server or it can be built into a stand alone network router or gateway If your network already uses a separate computer as a dedicated server you can use that computer as the VPN server A separate piece of hardware might be a better choice if your network does not already have a full blown network server Dozens of VPN equipment makers offer routers gateways and other products that support one or more of the VPN protocols Each of these prod ucts has a different feature set so testing the specific combination of client and server that you intend to use on your own network before you commit to them is essential The Virtual Private Network Consortium VPNC is moving toward a set of interoperability tests and certification standards much like the Wi Fi standards for wireless Ethernet equipment The VPNC website hitp www vpne org lists the products that have passed the interoperability tests and the site also provides links to information sources for a long list of VPN products NOTE Configuring a Windows Server for a VPN If you re committed to using a Windows server you can use either L2TP or IPsec with Windows Server 2003 or Windows Server 2008 if your server runs the older Windows NT Server 4 0 or Windows 2000 Server software you re limited to L2TP or the se
240. ment at the center of a star network that connects the computers and other nodes to one another and the related devices that provide connections between networks Unless you re connecting just two nodes these hubs switches and routers are essential network build ing blocks Hubs and Switches Chapter 3 Both hubs and switches are exchange points at the logical center of an Ethernet network as shown in Figure 3 2 Each computer or other network node connects to a hub or switch through a cable plugged into a socket called a port In a small network a hub or switch is almost always a tabletop box with indicator lights on the front and Ethernet ports on the back Ina larger network the hub or switch might be a panel that mounts in an equip ment rack Ethernet hub Figure 3 2 A hub or switch is the central connection point in an Ethernet network The maximum data transfer speed of a network is the data handling speed of the hub or switch You might find a 10 Mbps Ethernet hub but as faster devices have become less expensive there s not much reason to use one Today the most common hubs and switches are designed for both 10 Mbps and 100 Mbps operation The latest generation of switches and hubs supports even faster Gigabit Ethernet 1000 Mbps switches often at prices only slightly higher than those of older 100 Mbps versions Hubs When a data packet enters a hub the hub relays that packet to all of the hub s ports
241. meras or home automation combines TV and data network devices such as lighting or climate controls outlets to the network it s a good idea to mark their tentative locations Designing Your Network 49 Remember it doesn t cost anything to mark a location for an outlet on your floor plan You don t have to install every outlet right away but it s helpful to know where they re likely to be when you plan your cable runs You can always change the exact locations before you actually pull cable through the walls NOTE Planning for a lot of extra network connection points might seem unnecessary right now but that will almost certainly change If you plan for more network connection points than you think you need today you might have enough for the next ten years Consider this If you live in an old house with the original electrical wiring you probably know that one or two AC outlets in each room was considered more than enough back in 1925 more would have been extravagant Today you should have several electrical outlet plates on every wall In the future household data networks will be as common as electricity and telephones In your home consider placing at least one network outlet in each major room don t worry about hallways and other odd spaces In the kitchen place one outlet close to a counter and plan to place another on the wall next to the refrigerator and range You might also want an outlet in the laundry roo
242. mited to a single operating system whereas others offer compatible versions for exchanging messages between different computer types In most cases the same program must be running on each computer connected to the LAN you can t assume that two different LAN messenger programs will automatically recognize each other Softros LAN Messenger a SoftRos Lan Messenger hitp bue messenger softros com is typical of this TRENER DEST LE category As Figure 16 7 shows the General program displays a list of people 5 John Ross amp Ned who are currently logged into their computers with an icon that shows each person s status Available Busy or Away To send a message to another user simply click that person s name 8 Mv Info and type your message in the pop up Conversation window Figure 16 7 LAN messenger programs list the names of available users Other Network Applications 235 236 Chapter 16 When a message arrives the recipient s computer sounds a signal and displays the message in a pop up window like the one in Figure 16 8 The same window appears on both the sender s and the recipient s computers To continue the conversation type the text in the Message text box and click Send Ned Conversation IE Conversation 2 S sinvite 11 15 AM John Ross How about lunch Meat loaf special today 11 15 AM Ned Sounds good Let s go Close Figure 16 8 Both sides of a message exchange appear i
243. more of the attempts had taken around 500 milliseconds or more that would indicate some kind of problem Ping has also become a verb in computer jargon You ll hear a technician at a help desk ask you to ping me at a specific address meaning that you should send a ping request to that address Some people have extended that usage beyond computer networks They ll talk about pinging somebody when they intend to get that person s attention either by email telephone or even poking their head into the recipient s office Many large commercial Internet sites such as yahoo com and microsoft com have chosen to block ping requests from outside their own network If you get a no reply response to a ping request try another address before you assume the problem is with your own Internet connection TraceRovte The TraceRoute tool measures and displays the amount of time it takes for your computer to receive an echo from each network device between your computer and the target As a result a TraceRoute display can show you the route between your computer and any other computer on the Internet and pinpoint the segment of that route where a problem is occurring In Windows the command is tracert in OS X Linux and Unix it s traceroute TraceRoute sends three requests to each intermediate node and shows the timing for each request Listing 4 4 shows a TraceRoute from my office in Seattle to No Starch Press in San Francisco C gt tracert
244. my Windows desktop onto this monitor Men Troubleshoot Advanced 7 em o Figure 16 5 The Display Properties dialog includes an option that can extend the Windows desktop to two or more monitor screens Other Network Applications 231 232 Remote Control When you re already using two or more computers in the same room it s often a nuisance to move among the keyboards and mice that control them MaxiVista includes a Remote Control feature that allows a single keyboard and mouse to transmit signals through a network to multiple computers To use MaxiVista s Remote Control turn on Remote Control mode in the main computer and drag the mouse cursor to the desktop of the com puter you want to use When you select or open a program with the mouse connected to the main computer the main keyboard will work with that program The shared clipboard is part of MaxiVista s Remote Control function Simply use the mouse from the main computer to select and copy a file folder block of text or other object to the clipboard just as you normally copy objects on a local computer Then move the mouse cursor to the target computer open a program or select an already open window and paste the contents of the clipboard Synchronizing Files Chapter 16 Any time you collaborate with somebody else on a project you run the risk that each copy of the document or drawing or spreadsheet or any other record of your work will accum
245. n the conversation window The same program also allows users to transfer files through the LAN If you don t like the SoftRos package there are plenty of others each with a slightly different screen layout and features A web search for LAN messenger will produce dozens of links to descriptions and download sources Messaging Through a Virtual Private Network When you connect to a LAN through a virtual private network VPN the LAN treats your computer just like every other network node even through you might be hundreds or thousands of miles away from the rest of the network Chapter 13 explains how to set up and use a VPN VPN connections are commonly used for IM although you can also use a public IM service to accomplish the same thing To set up an IM through a VPN follow these general steps Establish your VPN connection to the LAN 2 Run your LAN messaging program Choose a connection through the VPN and select the person with whom you want to exchange messages Audio and Video Messaging In some situations there s value to adding sound and pictures in text messages The world s telephone companies spent many years and huge amounts of money trying to develop a successful commercial picturephone service as a supplement to traditional voice telephone calls but it never happened until they repackaged it as videoconferencing Adding pictures to telephone service seemed like a good idea but it turned o
246. n Figure 13 1 The fire wall monitors all inbound and outbound data between the computers on the local network on one side and the Internet on the other This kind of firewall is intended to protect the computers on the LAN from unauthorized intrusion from the Internet Firewalls in Wireless Networks In a wireless network a firewall can also be placed at the gateway between the wireless access points and the wired network This firewall isolates the wireless portion of the network from the wired LAN so intruders who have connected their computer to the network without permission can t use the wireless connection to reach the Internet or the wired part of the LAN Figure 13 2 shows the location of a firewall in a mixed network that includes both wired and wireless connections Figure 13 1 A network firewall isolates a LAN from the Internet Firewall B Pi point NX a Laptop Q Laptop a Laptop computer computer computer Figure 13 2 A firewall can also protect the wired portion of a LAN from wireless intruders Network Security 155 156 Chapter 13 A firewall in a wireless network can perform several functions e Itcan act as a gateway router between the wireless network and a wired LAN e Itcan protect a direct connection from a single computer to the Internet e Itcan block all traffic moving from the wireless side to the wired network that doesn t come from an authenticated user e It passes commands message
247. n control your house s heating and air conditioning systems open and close draperies adjust the lighting commu nicate with a burglar alarm or home security service operate lawn sprinklers and control the filters and temperature of your swimming pool among other activities The interface between the network and the control device can be either a direct Ethernet link or a controller that follows the low voltage X 10 standard Remote Sensors and Controls When you connect a remote interface device to your LAN you can monitor environmental conditions or the performance of unattended equipment and operate equipment by remote control through your network Many possible applications for this kind of networked remote activity are available including the following e Monitoring the temperature in an equipment room a freezer or cold box e Measuring and monitoring air or water temperature wind speed water flow in a stream or other body of water and other environmental conditions e Monitoring power levels e Monitoring and responding to alarms e Turning AC or DC power off and back on again in order to restart hung equipment e Monitoring normally open or normally closed intrusion alarms such as open doors or windows Other Things You Can Connect to Your Network 223 224 WARNING e Remotely controlling and adjusting isolated equipment e Tracking any other condition that can be measured or monitored with a digital
248. n of input and output Scanning Goes from a scanned image to a computer file Copying Goes from a scanned image to a printed page Printing Goes from a computer file to a printed page Incoming fax Goes from a telephone line to a printed page or computer file Outgoing fax Goes from a scanned image or a computer file to a telephone line 200 Chapter 14 Computers connected to the network treat an all in one device like each of the separate devices The printer shows up in the menu that Windows Mac OS or Linux Unix displays when you want to print a document like any other printer you must add it to each computer s printer list and load a printer driver on that computer The scanner uses either a TWAIN or WIA interface to import images directly into application programs and fax pro grams detect the all in one as a fax machine The copier function sends the scanned image directly to the printer so it doesn t show up on the network An all in one that is not intended for full network operation can still operate as a networked printer However it s possible that the scanner and fax functions will only work from the computer connected directly to the all in one unit As a rule of thumb you can assume that an all in one that connects directly to the network through an Ethernet port will support all of its functions from any computer on the network But if the unit connects to a printer through a USB port it might not accept commands from remo
249. n t turn on file sharing you won t be able to view or change files on this com puter through the network 10 Network Setup Wizard Figure 11 5 Select the file and printer sharing option that applies to your network The wizard will configure your computer for the settings you have selected When configuration is complete the Wizard will display the window shown in Figure 11 6 which offers to create a Network Setup Disk or finish the wizard Select the option that describes what you want to do If you select Create a Network Setup Disk you can use a floppy disk a USB flash drive or other removable disk as your setup disk Network Setup Wizard You re almost done Figure 11 6 The Network Setup Wizard will offer to create a Network Setup Disk Connecting Your Computer to a Network 121 122 Chapter 11 11 The wizard will follow your instructions and display the Completing the Network Setup Wizard window Click Finish Repeat the process for each Windows computer connected to your network If you created a Network Setup Disk or flash drive at the end of the Network Setup Wizard for the first computer you can use the program on that disk instead of running the Wizard each time Changing Your Computer s Network Settings To change one or more of your computer s network configuration settings manually follow these steps 1 From the Start Menu select Connect To Show all connections or from the
250. n you re not using a network in order to reduce battery drain and to avoid transmitting a signal that a hacker could use to link to your computer There are usually several ways to turn an internal adapter on and off a physical on off switch a set of keyboard commands and an option in the Wi Fi control program The com puter s user manual is the best source for instructions on operating a Wi Fi adapter PC Cards Laptop computers without built in adapters can use an adapter on a credit card size PC card or PC ExpressCard To install the adapter simply plug it into the PCMCIA socket and wait for your operating system to recognize it and load the appropriate driver software Figure 8 4 shows a PC card adapter The adapters extend about an inch beyond the edge of the PCMCIA socket in order to place the antenna outside the computer s metal case NOTE E Antenna inside this part Photo courtesy of D Link Figure 8 4 PC card Wi Fi adapters usually have built in antennas Some PC card adapters also have a connector on the top or on the outside edge of the card for an external antenna This can allow you to place the antenna in a location where there s a better signal to and from the base station but the separate antenna is one more thing to carry along with your laptop computer In general an adapter with a built in antenna is usually a better choice for a portable computer A few Wi Fi adapters are also available on the
251. nal from another computer in the same room and automatically set up a network link between the two devices It s best then to disable the infrared port anytime you re not planning to use it To disable or enable infrared communications in Windows open the Device Manager Control Panel gt System Hardware Device Manager expand the list of infrared devices right click the name of the infrared port and choose Disable or Enable from the pop up menu FireWire IEEE 1394 FireWire was developed by Apple as a high speed serial data transfer method for connecting computers to external accessories It was later adopted by the Institute of Electrical and Electronics Engineers IEEE as their Standard No 1394 IEEE 1394 is used most often for high speed data transfer from audio and video equipment to computers but it can also exchange data between two computers through a special cable Unlike FireWire it s not possible to use a simple cable between two computers USB ports as a communications link for direct data transfer However special USB Data Transfer Devices are available for this purpose Connections Through a Telephone Line When a high speed wide area network service such as DSL is not available you can connect your computer or LAN to the Internet or directly to a remote computer through the dial telephone system the Public Telephone Switched Network or PTSN also known as POTS short for Plain Old Telephone Ser
252. nce because they tell the computer where and how to find the operating system To run the BIOS settings utility turn off the computer then turn it on again and immediately press the DEL delete or F1 key depending on the type of BIOS your computer uses If you re not comfortable changing the BIOS settings just leave them alone When you install another network interface Windows and other operating systems will recognize both the internal and external adapters In most cases it won t matter if both of them are active at the same time On the other hand if your network connection doesn t work when you turn on the computer but the rest of the network is okay and all the network cables are plugged into their appropriate sockets it s possible that the internal adapter has been disabled by accident This should never happen unless some body goes into the BIOS utility and changes the setting but it s possible especially if the computer is in a public location where other people can mess with it Ethernet Network Interfaces 71 72 Adding a Network Interface to an Old Computer Chapter 7 If you re using an older computer it s possible that the computer does not have a built in network interface In that case you must add one before you can connect it to your network Fortunately network interface adapters are inexpensive and easy to install As a minimum look for an Ethernet adapter that can handle both 10Base T and 100Base T net
253. nd Novell include all the features of a simple file server along with many additional business functions such as web and email hosting calendar coordination remote access automated backup and data management all with a more or less consistent appearance These server packages are relatively expensive but their easy installation and available support might be worth the added cost especially in a large enterprise where additional support staff is an issue The developers of these commercial server products argue that the total cost of ownership TCO for their products including original purchase price and the cost of ongoing maintenance and support is about the same as the TCO of free Linux and Unix servers Microsoft claims that management and maintenance staffing plus downtime account for roughly 75 percent of a server s TCO but the experience of many open source software users is quite different In a very small business the numbers will probably work out in favor of free or inexpensive server software unless you have to pay for outside support If you re already committed to other Microsoft products including Access Microsoft SOL or Windows Media Windows Server is likely to be the best choice On the other hand many Linux and Unix versions include comparable programs such as the Apache web server that perform at least as well as or better than the Microsoft products If you re a Mac household or business Apple Server is the logical
254. ndows XP and those supplied with several major brands of network adapters automatically detect and display the SSIDs of every active network within their signal range It s not always necessary to know the SSID of a network before you try to connect the configuration utility or a network monitor or sniffer program like Network Stumbler will show you the names of every nearby network in a list or a menu the exceptions are networks in which the broadcast SSID feature has been turned off For example Figure 13 17 shows the result of a Network Stumbler scan at Seattle Tacoma Airport where Wayport served the passenger terminal and MobileStar provided coverage in the American Airlines VIP club Every access point comes with a default SSID setting and password These defaults are well known and documented within the community of network snoops run a web search for default SSID to find several lists Obviously the defaults should never be used in any active network Make sure you change the access point s administrative login and password while you re at it 4 Network Stumbler Stumbl1 x l Eile Edit View Options Window Help lel x D d P eas t aat W Channels MAC SSID Name Chan Vendor s SSIDs 900409 Wayport Access 6 Cisco Aironel F Filters 900409 MobileStar 1 Cisco Aironel 2 Ready 2 APs active GPS Disabled Figure 13 17 Network Stumbler and many configuration utilities di
255. ne between the WAN and the rest of the Internet the subnet mask tells the WAN which numbers in the router s IP address identify the router and which generic numbers identify the WAN For example the most common subnet mask is 255 255 255 0 which means that the last of the four numbers is different for each node In other words if your WAN controls all the addresses in the 123 223 123 XXX group your address might be 123 223 123 103 and another customer s address on the same WAN might be 123 223 123 117 The specific numbers your router uses are absolutely essential if you don t have them exactly correct the router won t connect to the Internet But understanding what they mean is less important than getting them right Your Internet service provider will supply the numbers to use when you set up a new account Write the numbers in the same place where you keep account numbers and other important computer related information Connecting Your Network to the Internet 109 110 NOTE NOTE Chapter 10 When a separate DSL or cable modem is between the gateway router and the Internet the modem often provides the static IP address and other information to the Internet and the local network In this situation the gateway router relays the necessary addresses between the modem and the rest of the local network The LAN settings for your router or modem control the way your local network operates The specific settings in each computer connec
256. net 23 39 158 Temporal Key Integrity Protocol TKIP 182 183 text messaging 233 TightVNC 226 229 Time Machine 103 104 104 TiVo 216 216 217 TKIP Temporal Key Integrity Protocol 182 183 top level domain names 39 41 40 topologies 27 28 28 total cost of ownership TCO 95 TraceRoute tool 36 44 44 46 45 tracert 44 traffic monitors 204 trailers 11 transceivers 80 81 transmission control protocol TCP 35 36 123 123 126 158 service ports 158 Trend Micro HouseCall 245 TRENDnet 161 Trillian 234 troubleshooting AC power 242 configuration settings 246 defining problems 240 241 DHCP settings 246 error messages 229 239 240 241 247 failed connections 246 247 general techniques 239 245 isolating problems 243 ISP problems 251 keeping calm 251 note keeping 244 245 operating systems 240 plugs and cables 242 restart options 241 242 retracing steps 243 settings and options 243 software for 248 250 249 250 viruses 245 TrueCrypt 185 tunneled virtual interfaces 164 tunneling headers 161 162 TV cable connections 65 66 TVs 206 218 220 TWAIN interface 201 twisted pair cables 15 15 U UItraVNC 229 uncompressed audio files 209 210 U NII Unlicensed National Informa tion Infrastructure 79 United States Computer Emergency Readiness Team US CERT 189 niterruptible power supply UPS 61 Unix backup files 100 104 computer to network connections 117 127 127
257. networked receivers 214 Network Magic 248 249 249 Network Monitor 248 250 networks control centers designing 50 53 installing 58 68 60 63 65 for small networks 25 67 68 control devices 33 37 61 111 115 defined 1 3 designing 47 54 48 49 52 53 discovery 137 error messages 229 239 240 241 247 gateway configuration 115 hubs 120 installation cables 56 57 cable TV connections 64 66 connectors 55 56 control centers 50 53 58 68 60 63 65 DSL connections 22 62 64 99 expanding 67 small networks 25 67 68 surface boxes 55 56 telephone lines connecting 64 65 65 terminating network cables 66 67 wall plates 49 49 50 52 55 56 56 67 wiring 16 17 57 67 66 interface adapters Wi Fi 81 85 82 83 84 85 87 names See SSIDs notebooks 244 245 planning for 47 54 48 55 problems See troubleshooting profiles 118 security See also encryption methods access levels 152 administrators 152 Baseline Security Analyzer 188 188 controlling users 189 DoS denial of service attacks 189 firewalls 90 91 154 159 155 158 164 172 176 guest accounts 152 intruders 152 159 174 IP filters 159 MAC authentication 184 185 naming networks 177 179 178 passwords 90 133 136 154 143 152 154 154 205 physical security 184 185 port assignments port numbers 157 158 158 sneakernets 4 updates and patches 185 188 186 187 user accounts 152 wireless security 54 89
258. networks can operate at speeds up to 70 Mbps A 10Base T network is adequate for a small home network It s faster than most broadband Internet services so it s sufficient for handling the inbound and outbound data including audio and video that you exchange with the Internet However most new network ports hubs and switches can handle both 10Base T and 100Base T so there s very little point to limiting the network to the slower speed 100Base T will also allow you to move pictures music and videos and play multiplayer games within your own network much faster than a 10Base T network and it will not limit the speed of an 802 11n link Considering the insignificant difference in cost today s 100Base T networks are always a better choice than the older 10Base T versions Ifa 100Base T network can t handle 100 Mbps because of interference or some other problem it will automatically drop down to 10Base T A 10Base T device can work on a 100Base T network but it will force the whole network to drop down to 10 Mbps A Gigabit Ethernet network is lightning fast by today s standards but it s also more expensive than a network that uses slower equipment It might be appropriate for a business that moves very high volumes of data through its LAN As the cost of Gigabit Ethernet drops it will become the preferred choice for home and small business networks You might also see the word Ethernet used to identify the connector on a
259. nfo nostarch com www nostarch com Library of Congress Cataloging in Publication Data Ross John 1947 Network know how an essential guide for the accidental admin John Ross p cm Includes index ISBN 13 978 1 59327 191 6 ISBN 10 1 59327 191 3 1 Home computer networks 2 Computer networks Management I Title TK5105 75 R667 2009 004 6 dc22 2008052768 No Starch Press and the No Starch Press logo are registered trademarks of No Starch Press Inc Other product and company names mentioned herein may be the trademarks of their respective owners Rather than use a trademark symbol with every occurrence of a trademarked name we are using the names only in an editorial fashion and to the benefit of the trademark owner with no intention of infringement of the trademark The information in this book is distributed on an As Is basis without warranty While every precaution has been taken in the preparation of this work neither the author nor No Starch Press Inc shall have any liability to any person or entity with respect to any loss or damage caused or alleged to be caused directly or indirectly by the information contained in it www allitebooks com BRIEF CONTENTS Acknowledgments eode testet eese tr estne E Foe pede ges Ponte ed oreet xiii iren xv Chapter 1 How a Network Will Improve Your Life sss 1 Chapter 2 Types of Network Connections sss eee 9 Chapter 3 Hubs Switches and Rout
260. ng a Folder Sharing CO Share this folder Share this folder Share name bin Allow other people to write in this folder Comment Guest access for people without a user account cancel E create Share Figure 12 17 Use the Folder Sharing Figure 12 18 When you turn on the Share dialog to configure a directory as a this folder option the Folder Sharing dia network share log reveals more options 4 Select the options you want to apply to this share and click the Create Share button to save your choices Sharing from Konqueror If your desktop uses KDE and Konqueror follow these steps to create a share 1 Right click the folder or drive you want to share 2 Select the Permissions tab in the pop up Properties window as shown in Figure 12 19 Sharing Files Through Your Network 149 150 General Permissions Access Permissions Owner Can View amp Modify Content gt Group Can View Content Others Can View Content C Only owner can rename and delete folder content Advanced Permissions Ownership User jmr Group jmr L Apply changes to all subfolders and their contents X canca Figure 12 19 Konqueror s Permissions tab controls network access to a folder s contents 3 To configure a folder as a share use the drop down menus next to Group and Others to change access permissions and check the Apply
261. ng and security To share this folder with both network users and other users of this computer select the first check box below type a share name e this folder on the network name are T Allow network users to change my files Leam more about sharing and security Windows Firewall is configured to allow this folder to be shared with other computers on the network Mew your Windows Firewall settings 9 cw Figure 12 3 Select Share this folder on the network to assign a drive or folder to Level 4 Sharing Files Through Your Network 135 136 3 In the Network Sharing and Security section of the Properties window check the Share this folder on the network option 4 Make sure a checkmark does not appear in the Allow network users to change my files checkbox Click the box to remove an existing checkmark 5 Click OK to save your changes and close the Properties window Level 5 Level 5 drives files and folders have no protection against changes or deletions by any network user Anybody with access to a Level 5 file whether on the same computer or through the network can add change or delete that file In a Level 5 folder any user can also create a new file or folder or delete an existing one Obviously Level 5 is the lowest level of security essentially no security at all so you should only use Level 5 for files that you want to allow everybody on the network to change or delete As added protect
262. ng and security er To share this folder with other users of this computer only drag it to the Shared Documents folder To make this folder and its subfolders private so that only you have access select the following check box Make this folder private r Network sharing and security 33 To share this folder with both network users and other users of this computer select the first check box below and type a share name Share this folder on the network Share name Photos Allown Learn more about S lange my files X Windows Firewall is configured to allow this folder to be shared with other computers on the network View your Windows Firewall settings m wm Figure 9 2 Set sharing permissions for the folder that holds the files you want to store on your server When you work on a document or any other type of data file and when you download a file from the Internet use the Save As command to store the file through the network in one of the shared folders on the server To read view or listen to a file stored on the server either open the folder that contains the file you want and select the file or use the Open command in a program associated with that file type such as a word processor spreadsheet or media player and use the selection window or chooser to find the file The program should treat the file exactly the same as a file stored on your own computer Using N
263. nnect to Your Network 209 210 NOTE Chapter 15 Table 15 1 Common Audio File Formats File Extension Format Name Description wav WAV or Wave This is Microsoft s format for uncompressed audio Waveform Audio which has since been adopted by others It is widely used in audio archives mp3 MP3 or MPEG This is a compressed format for consumer audio It s not Layer 3 a high fidelity format but it is good enough for casual listening ogg Ogg Vorbis This is an open source compressed format It is widely used for free content flac Free Lossless Audio This is a compressed format that does not remove Codec FLAC content from the compressed file unlike MP3 or Ogg Vorbis Because this format is lossless a FLAC file is a more accurate copy of the original than other compressed file formats aiff Audio Interchange This is an uncompressed format introduced and mainly File Format used on Apple computers wma Windows Media This is a compressed format developed by Microsoft Audio and mainly used with Windows Media Player but it s also supported by other players ra or ram Real Audio Th is is Real Audio s family of formats for streaming Internet audio It is widely used by radio stations including the BBC bwv Broadcast Wave This is an uncompressed format established by the European Broadcasting Union for digital storage of audio files It is similar to WAV with additional space for metadata information about each file
264. nnected to this network Add Printer Wizard 4 Browse for Printer When the list of printers appears select the one you want to use Printer Shared printers s Microsoft Windows Network DESKTOP Samsung ML Samsung ML 1740 Sene B DESKTOP Printer information Comment Stalus Documents waiting Figure 14 5 The Browse for Printer screen shows a list of all the shared printers connected to this network 5 Select the name of the printer you want to use and click Next The wizard will ask if you want to use this printer as the default 6 Ifyou want this computer to send print jobs to this printer as the default click Yes If you want it to appear in a menu as a secondary choice click No 7 Click Next The wizard will confirm that you have added the printer to this computer s list 8 Click Finish to complete the wizard and close the window The name of the newly added printer should be visible in the Printers or Printers and Faxes window The process is similar in Windows Vista but the Add a printer command is in the toolbar directly above the window as shown in Figure 14 6 Click Add a printer 2 Click the Add a network wireless or Bluetooth printer option The wiz ard will display a list of all shared printers and printer servers connected to this network 3 Select the printer you want to use from this computer and click Next 4 The wizard will add this printer to your list
265. nostarch com Tracing route to nostarch com 72 32 92 4 over a maximum of 30 hops 1 4 ms 3 ms 3 ms 192 168 0 1 2 3 ms 3 ms 3 ms 192 168 0 1 3 71 ms 63 ms 64 ms blv nwnexus net 206 63 4 57 ms 53 ms 48 ms fe000 cr1 sea nwnexus net 206 63 74 1 5 44 ms 42 ms fe000 br4 sea nwnexus net 206 63 74 20 6 45 ms 43 ms 41 ms 204 181 35 197 7 42 ms 42 ms 43 ms sl bb20 sea 4 0 0 sprintlink net 144 232 6 121 o 8 9 10 11 12 13 14 15 86 ms 85 ms 87 ms sl bb25 chi 5 O sprintlink net 144 232 20 84 96 ms 97 ms 97 ms sl bb20 kc 2 0 sprintlink net 144 232 20 108 108 ms 109 ms 107 ms sl crsi fw 0 4 0 1 sprintlink net 144 232 20 56 110 ms 110 ms 108 ms sl st20 dal 1 O sprintlink net 144 232 9 136 99 ms 98 ms 97 ms sl racks 5 O sprintlink net 144 223 244 138 101 ms 98 ms 97 ms vlan903 core3 dfwi1 rackspace com 72 3 128 53 101 ms 100 ms 98 ms aggrii5a dfwi rackspace net 72 3 129 109 97 ms 100 ms 99 ms squidi4 laughingsquid net 72 32 92 4 Trace complete Listing 4 4 TraceRoute shows the path to a distant computer through the Internet In this case it took 15 hops to complete the connection The first two lines show the very fast response from the router sitting on the same table as the computer through a 6 foot cable Line 2 repeats line 1 because of a software problem in the router Line 3 whose domain name and IP address I have hidden is my Internet service provider s WAN a couple of miles aw
266. now how it works even if you choose not to use it As the name suggests the original intent of the wired equivalent privacy WEP protocol was to provide a level of security on wireless networks that was comparable to the security of a wired network That was the goal but a network that depends on WEP encryption is almost as vulnerable to intrusion as a network with no protection at all WEP will keep out the casual snoops and your free loading neighbors if they re not particularly adept at cracking encryption but WEP is not particularly effective against a dedicated intruder The more recent WPA encryption is always the better choice WEP encryption is intended to serve three functions It prevents unauth orized access to the network it performs an integrity check on each packet and it protects the data from eavesdroppers WEP uses a secret encryption key to encode data packets before a network client or an access point transmits them and it uses the same key to decode packets after it receives them The original standard used shared authentication in which the access point sends a challenge packet that a client must encrypt with the proper WEP key and send back However this opens a significant vulnerability by allowing a snooper to watch both parts of the exchange and derive the key The open authentication method which should be used by any net work using WEP not that any network should use WEP simply discards packets that
267. nsecure system Limit file shares to the files that you really want to share don t share entire drives Use password protection on every share Use the same firewall and other security tools that you would use on a wired network At best the wireless portion of your LAN is no more secure than the wired part so you should take all the same precautions Consider using a virtual private network VPN for added security Use a firewall program on every computer connected to the network including both wired and wireless nodes Wi Fi Networks 91 92 Chapter 8 It s important to take wireless network security seriously but don t let the security issues discourage you from using Wi Fi in your home or office unless you re moving very sensitive information through your network If you protect your network with encryption and other security tools you will probably keep all but the most determined hackers and crackers on the outside On the other hand if your small business handles customer billing information credit card data sensitive client or patient records personnel data such as Social Security numbers or any similar information that should remain confidential adding Wi Fi to your LAN creates an extremely attractive target If you must add Wi Fi access to your small business network use the strongest firewall you can find between the Wi Fi access point and the other computers on the network FILE SERVERS File serv
268. nt The client can be a program running on one or more of the household computers a stereo component a surround sound or home theater system or a tabletop boom box or Internet radio The client receives music files from a server or streaming audio program through the Internet and plays them through a set of headphones or speakers The quality of sound played through a network depends on several factors the quality of the original recording the amount of network traffic and the quality of the client s digital to analog converter and speakers For example if you re playing a music track that originated on a noisy cassette tape through the tiny and tinny speakers in your laptop computer the music will sound much worse than a track ripped from a CD and played through a good stereo amplifier and high fidelity speakers And if the network that connects the server to the client is already running close to its capacity or if it s using a noisy Wi Fi link you might hear repeated drop outs in the music when the client can t convert data packets to a continuous audio stream Playing Music Through a Computer A computer used as a music client must have an internal or external audio interface such as a sound card an interface on the computer s motherboard or an interface connected to the computer through a USB or FireWire port To play a music file open the file in an audio player program that supports the file s format just as you wo
269. ntosh Computer to a Network sssssse 124 Connecting Your Linux or Unix Computer to a Network sem 127 SUMMARY c5 os Ls teer een add te Sl Met coal eee ERE E POR pet ott 129 Contents in Detail ix 12 SHARING FILES THROUGH YOUR NETWORK 131 File Sharing in Windows XP sseceseeeceeseesseeneeeeteeceecneeeneesaesneeenseenteeesieenseenaees 132 Level Wes eben tate re textes odi n delest btee tita ecib ne to etie leet 133 Level 2 4 cre et ptt t te e te a di tea ee ete deter es 134 Level 3 citate t ctt dashes aeter dE eget eee iio lr Se itia 135 FOOD M M 135 level S3 cedet ique mtteaetatenedenit eite eese Mene ttaledonetgetes 136 File Sharing in Windows Vista sse eene 136 Nenwork Dis oVery coe eta MM A oce ree der ede ee Ee tees 137 File Sh ringi teneor er oper en he teer tete beached qusiess 137 Printer Sharing ecrit e Rope P b TERI Hx PR it cse ERR Fee CEPR ce 143 Password Protected Sharing 143 Mediai Sharifig ur e an ALD rss deesse iee a e tetas em o 143 File Sharing ona Macintosh cto it a enesi Meet e need EE ve ved 143 Connecting a Mac to a Windows SMB Network 143 Connecting from Older Mac Versions sss e 147 File Sharing in Linux and Unix sese e eem emen 147 Sharing from Linux or Unix Computers sss 147 Creating Shares on Linux and Unix Computers sse 149 Samba 353 eti e beer eR eter ere tede te Lee oe b ae
270. ntosh OS X and several versions of Linux and Unix I ll also tell you about some other ways you can use your network including automating household appliances and distributing digital audio and video to computers home entertainment systems and Internet radios throughout your house The ideal network is the one that you and the other people using your network never have to think about You would plug a cable from each computer into an outlet and every other computer on the network would immediately recognize it And the network would simply be there ready to use Or it would be completely invisible like the wires that provide electricity to the lamp next to the chair where you re reading this If you think about it you don t really want a network you want to see and hear files and other resources that are located beyond your own computer A network is the means to that end As I wrote this book I kept several goals in mind First I wanted to provide enough information that readers with some basic computer knowledge and skills could understand how networks work and how to plan and install their own small network second I wanted readers to think about additional uses for their networks and third I wanted to offer advice and tools for fixing a network that isn t working correctly If I have succeeded your network will be up and running shortly after you follow the book s instructions and recommendations Network Know How begins with
271. o distribution system along with your data network and you have to install your own cable from the service entry to the network control center it might be easier and cheaper to buy a pre assembled cable with the connectors already attached look for a cable close to the length you need don t use a 100 foot cable for a 20 foot run Use electrical tape or a cable tie to hold excess lengths of cable in a neat loop at one end If you have to install the video cable yourself find the service entry where the cable comes into your house or office String the cable along the ceiling or through the rafters under the floor to the control center then attach the cable to the F connector inside the outlet plate If there s a splitter with a spare connector at the service entry screw the plug at the end of the cable onto the unused socket If you can t find a splitter you ll have to install a new one or distribute your video from the control panel Installing the Network Control Center and Ethernet Cables 65 66 Chapter 6 If you re not connecting other outlets through the control center plug the cable from the service entry directly into your cable modem If you want to use the control panel to distribute cable TV signals to outlets throughout the house connect the cable from the service entrance to the input of a splitter and connect the outputs to your cable modem and the cables from each room Terminating the Network Cables If you
272. o hide cables and holes behind mop boards and other moldings After the wires are in place you ll have to patch the holes and repaint the walls Use an electrician s snake to pull or push cables through places that you can t reach with your hands When the end of the snake reaches the target location attach the end of the bulk cable to the snake with electrical tape and pull the snake and cable back from the other end It s a lot easier to route wires with a rigid snake a long thin piece of metal than to deal with loose cable flopping around inside a wall Remember to add a length of heavy twine as a pull line along with each cable or cable bundle that you pull through the walls In the future when you want to add another cable along the same route you can attach the cable to the pull line and pull it through without the need to create new holes in your walls You re going to connect a lot of cables to and through the control center so you will want to keep them out of sight in order to maintain a neat and clean appearance A 2 inch PVC pipe at the back of a closet or in some other hidden location can provide an inconspicuous route for cables between an upper floor or the attic and the basement or crawl space If the pipe runs through the space where the control center is located assemble a channel from two shorter pipes and a tee fitting about four or five feet above the floor Pipes fittings and glue are all available at your local hardwar
273. o identify the computers and other devices connected to a network and the people who use them Every computer connected to a network has a unique name and address within that network and every network connected to the Internet has its own unique numeric Internet address known as an JP address Numeric Addresses The technical committees international standards organizations and government agencies that manage the Internet have all agreed on a 32 bit numeric address format shown as four numbers between 0 and 255 separated by periods like this 192 168 3 200 When you read an IP address out loud you pronounce each digit separately and each period as dot So you would read this sample address as one nine two dot one six eight dot three dot two zero zero You can think of an IP address as similar to your telephone number Every computer connected to your LAN and every device or network connected to the Internet has a different address The agency responsible for assigning numeric IP addresses on the Internet is the Internet Assigned Names Authority IANA Some formal contracts with the US government are involved but the real reason IANA can provide this service to the worldwide Internet community is that every body agrees to respect their assignments As the owner of a small LAN you will never deal directly with IANA Your Internet service provider controls a block of numeric addresses and it will assign you one address or
274. o one of your computers but that might limit your opportunities for easy expansion of the network in the future 50 Chapter 5 www allitebooks com If you plan to distribute audio video telephone or home automation wiring around the house along with computer network data your control center should have enough space for all of the necessary equipment required by all those services It will be easier to pull two or more types of cables at the same time than to install each type separately A network control center can have several possible forms It could be a simple plywood panel attached to the wall or it might be a pre wired modular cabinet mounted on a wall or between the wall studs Or if you have the floor space it might be in one or more freestanding equipment racks The control center s location should have the following characteristics e Itshould be easily accessible Don t choose a location that forces you to climb over bicycles and storage boxes or push clothes on hangers aside to reach it e Itshould have enough light to allow you to see what you re doing at any time of day or night e Itshould be in a place that remains dry and has a stable temperature e Itshould be close to at least one electrical outlet e Itshould be relatively central in order to reduce the length of connect ing cables e Itshould be at or slightly below eye level so you can work comfortably e Itshould have enough space to allow for
275. o your network is similar to adding a computer except that you ll have to configure the printer server remotely from a com puter The usual routine is to connect the server to the network and the printer to the server and then use a web based configuration utility to set the server s network address and other options Follow the instructions supplied with the server to load the printer driver Another advantage of using a printer connected directly to the network is that it operates independently of the other computers on the network When a printer connects through a computer that computer must be on all the time or you have to create a public account that the rest of the family or office can use to print This setup is a lot less secure than printing through a server Printers and Other Devices on Your Network 193 194 WARNING Chapter 14 Wi Fi Printer Servers If your network already includes a Wi Fi access point you can use a Wi Fi printer server to connect your printer to the network The printer server should automatically detect the Wi Fi signal from your access point and establish a two way connection data in and printer status out between the printer and the computer that originated the print request The Wi Fi link should use all the same security tools such as WPA encryption as your other Wi Fi connections A Wi Fi printer shares the same wireless channel with other Wi Fi links on your network so a large document might
276. oad win 98 Install 1 0 W9XNT4Me EN US msl2tp exe Making the Connection in Windows When the VPN connection profile is in place it s easy to connect a Windows client to the host LAN or the Internet through the wireless VPN link Just double click the icon for the connection profile Windows will ask for a login and password and then make the connection If you mostly use your wireless connection to connect to the Internet you can make it the default connection which will open whenever you run a Network Security 169 170 Chapter 13 network application such as a web browser or email client program To make the VPN profile the default follow these steps 5 Open the Internet Properties window from the Control Panel Select the Connections tab In the Dial Up Settings section select the VPN connection profile from the list and click the Set Default button Click the Settings button In the Dial Up Settings section type your login and password on the VPN server Select the Dial whenever a network connection is not present option Selecting Windows XP and Vista Options Windows XP and Windows Vista offer many VPN options that were not available in earlier versions of Windows To set these options follow these steps l Choose the Network Connections window from the Control Panel Ifyou have a shortcut to your VPN connection on the desktop you can skip this step Double click the VPN icon A Connect VPN to Interne
277. odular structured wiring center 59 63 modulation 6 108 monitors multiple 229 232 230 231 motherboards 70 mounting brackets 56 56 mounting frames 59 MPEG Layer 3 MP3 files 208 209 210 210 MPlayer 218 MSN Messenger 158 Multimedia over Coax Alliance MoCA 17 music clients 211 212 213 devices 213 214 214 music servers 7 8 24 207 209 212 213 213 Muuss Mike 43 name 40 names and addresses 36 41 NAS network attached storage devices 93 95 97 98 98 100 108 NAT Network Address Translation 37 67 157 158 159 National Electric Code 51 Nautilus file browser 147 148 148 net 39 40 NetBEUI networks 162 NetBSD 159 164 173 Netgear 161 213 216 Netscape Navigator 174 network adapters for laptops 73 74 74 USB 73 Network Address Translation NAT 37 67 157 158 159 Network and Sharing Center 136 138 137 138 network applications MaxiVista 229 232 230 messaging 233 237 multiple monitors 229 232 230 231 overview of 225 remote controls 232 remote desktop programs 226 229 227 228 network attached storage NAS devices 93 95 97 98 98 100 108 network commands ifconfig 43 IPConfig 41 43 42 ping 36 43 43 44 TraceRoute 36 44 44 46 45 network compatible home appliances 223 INDEX 259 260 INDEX network configuration settings 117 129 118 129 network connections computer to network Linux 117 127 127 129 12
278. of pixels within a l inch 2 5 cm square space on the screen or any other image area Other Things You Can Connect to Your Network 219 220 To show a computer image on a TV screen the controller must adjust the number of scan lines or pixels to fit the area available on the monitor If the TV screen expects more scan lines or pixels than the incoming signal the controller will duplicate occasional lines or pixels or it will create a new line that is a blend of the one above and the one below If the computer sends too many scan lines or pixels the screen will skip some of them This process is called video scaling Video scaling has two effects It forces the video controller to work hard to change the size and sometimes the shape of the image which can slow down performance and it sends an image to the TV screen that can suffer from smeared colors looser focus jagged edges and distorted pictures A good controller can make adjustments that minimize these problems but don t be surprised if the image your computer displays on a TV screen even avery good high definition TV screen is not as sharp as the same image ona computer monitor a good DVI to HDMI image on an HDTV can be sharper than a VGA display when everything works together correctly but a mis matched system can be considerably less impressive Game Consoles Chapter 15 The most widely used game consoles Sony PlayStation2 or PlayStation3 Nintendo Wii and Xbox 36
279. oint or other device that normally acts as DHCP server for your network If the server is active and other computers on the network are connecting normally the problem is in your computer if it s not active either turn it on or confirm that this network doesn t use DHCP 2 Open the network configuration settings utility in your computer If the DHCP server is active confirm that the computer is set to accept data from the server if the network does not use DHCP make sure the addresses for the DNS server and the default gateway or gateway router are correct If the DNS server settings in your computer or DHCP server appear to be correct it s possible but unlikely that the DNS server itself is not working Try adding the address of one of the OpenDNS servers 208 67 222 222 or 208 67 220 220 as an alternative to your usual DNS server s address Failed Connection to a Specific Site When you try to connect to a specific website or other Internet service you will sometimes see an Unable to connect message instead of the web page or other screen you were expecting When this happens immediately try some other address that takes you to a site in a different geographical location for example if you can t connect to The New York Times website try a site based in Germany or Australia If you can connect to the second address you can safely assume that the problem is at the first address and not in your own computer or net
280. okmarks Tools Settings Window Help Qooco Pe a 0na E gt Location A smb local SSystem FA smb flocal a Home Folder e amp Lj Remote Places C 7 L E E Network Services e EERE TEs Desktop Tower Ej Local Desktop Tower Co Ej Mygroup Storage Media s Trash Ay Users Folders Al B 5 a uw j 2 Items No Files 2 Folders eee Figure 12 16 In Konqueror network computers are accessible as Samba Shares under Remote Places Click an icon to open a drive or folder 148 Chapter 12 Both Nautilus and Konqueror are basic graphic browsers that support the usual set of file management activities You can click an icon to open a folder or a file or drag and drop to copy a file from one computer to another Creating Shares on Linux and Unix Computers The general procedures for creating a shared directory in Gnome and KDE are similar Open a browser window that contains the directory you want to share right click the directory and change some settings Sharing from Gnome From a Gnome file browser follow these steps to create a share Right click the folder you want to share A pop up menu will appear 2 Choose Sharing options from the menu The dialog shown in Figure 12 17 will open 3 Check the Share this folder option The additional options shown in Fig ure 12 18 will become available a File Manager MEIE File Manager MEIE m Folder Shari
281. olver described in The Collective Wisdom of the Internet on page 247 for com puters using Windows or search for information about the problem in the web pages devoted to your own operating system Troubleshooting 245 246 Chapter 17 Configuration Settings When you can t connect your computer to the Internet but other computers on the same network can connect check the computer s network configura tion settings to confirm that the default gateway and the DNS server are present and correct If none of the network s computers can find the Internet check the settings on the network s router or modem To confirm that the gateway and the DNS server are alive and operating properly try sending ping requests to their numeric addresses If you don t receive a reply look for a problem in the gateway or the server or in the equipment and cables between your computer and the target DHCP Settings DNS and Default Gateway When a DHCP server is active on your network and your own computer or the one you re troubleshooting is set to accept DHCP settings the computer should automatically connect itself to the network But if there s no DHCP server or if the computer is not configured to accept DHCP data from a server and the settings on the computer itself are missing or incorrect the computer won t connect To confirm that the DHCP settings are correct follow these steps 1 Check the modem router Wi Fi access p
282. on Some access points can also accept commands through a wireless link but after you turn off the wireless function you ll need a wired connection to turn it back on again Wi Fi Networks 85 86 Chapter 8 The most common method for configuring an access point is through a web based configuration utility In other words the access point s configur ation options all appear on one or more web pages that appear when you point your computer s web browser to the access point s IP address Each make and model of access point uses a somewhat different config uration program so the manual supplied with each device is your best source of specific instructions However they all include similar options The most important settings include DHCP Many networks use Dynamic Host Configuration Protocol DHCP to automatically assign IP addresses from a DHCP host or DHCP server The alternative is to manually assign a numeric IP address to each computer and other device connected to the network The access point s configu ration utility includes an option to use the access point as the network s DHCP server IP address You must either set the access point to accept an IP address from another device a dynamic IP address or manually enter an address for the access point Wireless network name Each network should have a distinctive name called a Service Set Identifier SSID This is the name that users will select from a list of net
283. on the network nodes located at the fringes of the access point s coverage area Many Wi Fi adapters and access points use antenna connectors that are not the same as the standard cable connectors on antennas In order to match the two you must use a short cable adapter not to be confused with a network interface adapter called a pigtail Pigtails are often available directly from the companies that make Wi Fi adapters and access points but these OEM original equipment manufacturer parts are extremely expensive Cables that do the same job equally well are available for a fraction of the OEM prices from specialty cable suppliers Run a web search on Wi Fi pigtails to find a place where you can order inexpensive adapter cables Wi Fi Control Programs Before you can move data through a Wi Fi network you must configure the network s base station to specify the operating channel you want to use the password for data encryption and other characteristics of the network In addition each wireless network adapter must also run a control program Access Point Configuration Programs Your access point should have at least one wired connection to a computer in order to set and change the configuration settings Depending on the make and model you re using this connection might be through an Ethernet port a USB port or a serial data port The access point uses this connection to accept configuration and setup commands and to send status informati
284. onal hard drives The sound quality of the most common sound cards and built in sound processing on many motherboards is adequate for casual listening However the quality is not as good as an audiophile or studio quality sound card or external interface unit that adds less background noise and distortion to your files If you re creating your own files from CDs or uncompressed digital program sources you will probably want to upgrade your sound card from the Sound Blaster interface supplied with your computer On the other hand if you get all your music by downloading MP3 files from iTunes or one of the other online services or if you convert your music from CDs LPs or other sources to highly compressed MP3 files you won t notice the difference The choice of operating system Windows Macintosh or Linux is a matter of personal preference all three can work as music servers If you re already using Windows Home Server to control your home network and share other files the same server can stream audio and video to other network computers Microsoft s Windows Media Center included in some versions of Windows Vista and available as a separate add in product is primarily a media player but when you connect it to a device that has the Media Center Extender technology in place you can use the Media Center computer to serve audio and video files to other computers game consoles and televisions For mixed networks XMBC
285. one or cable TV outlet in your control center This is the same kind of outlet that you are already using to connect a telephone or TV set If you re getting Internet service from your cable TV company you can sometimes convince the installer to run a cable to your control center But if you have DSL or some other type of Internet service from the telephone company you might have to install your own wiring Connecting a Telephone Line If you have DSL or some other kind of Internet service from the telephone company you will need a telephone outlet with a four pin socket called an RJ 11 jack This is the same kind of socket that you use to plug in a tele phone set Mount the outlet block on your panel about a foot above the power strip You can use either conventional telephone cable with two pairs of wires inside or the same four pair data cable that you use for your computer network to connect the outlet block on the control panel back to the distri bution block that connects your telephones to the service entry If you use telephone cable be sure to match the colors of the wires to the letters on the outlet blocks at both ends R red Y yellow G green and B black If you use data cable use the color codes in Table 6 1 Table 6 1 Data Cable Color Codes for Telephone Lines Terminal Color Data Cable Color Green Blue Red Blue White Black Orange Yellow Orange White Use a cable stripping tool to remove about two in
286. onitors e A rectangular multipin digital input known as a digital visual interface DVI connector e A19 pin or 29 pin digital socket known as a High Definition Multimedia Interface HDMI connector The easiest way to feed a signal to your TV from the computer is to find a video controller for your computer that has outputs that match your TV s inputs but that s not always possible For example you won t find a video controller that can directly feed an old analog TV with nothing but an F connector as signal input or an even older set with screw terminals The alternative is to use some kind of adapter a special cable with different cables on each end or a converter that changes the output signal from the computer to a signal compatible with the TV s input For best quality with an HDTV screen use either a DVI to DVI cable or a DVI to HDMI cable or adapter depending on the TV s inputs Look for an adapter or converter at an electronics retailer Video Output Drivers Driver software for video controllers can come from several possible sources bundled with your computer s operating system or supplied by the maker of the video controller or the controller s chipset or with a video converter The control program for each driver package is different so you ll have to follow the printed or onscreen instructions when you install the software Video Scaling Putting aside the issues related to converting between analog and digital
287. ons of millions of their customers eff org nsa FREE SPEECH EFF s Coders Rights Project is defending the rights of programmers and security researchers to publish their findings without fear of legal challenges eff org freespeech INNOVATION EFF s Patent Busting Project challenges overbroad patents that threaten technological innovation eff org patent FAIR USE EFF is fighting prohibitive standards that would take away your right to receive and use over the air television broadcasts any way you choose eff org P fairuse TRANSPARENCY EFF has developed the Switzerland Network Testing Tool to give individuals the tools to test for covert traffic filtering eff org transparency INTERNATIONAL EFF is working to ensure that international treaties do not restrict our free speech privacy or digital consumer rights eff org global E F F ER ie ELECTRONIC FRONTIER FOUNDATION EFF is a member supported organization Join Now WWW eff org Support STEAL THIS COMPUTER BOOK 4 0 UBUNTU FOR NON GEEKS SRD EDITION 2ND EDITION HACKING THE ART OF EXPLOITATION JON ERICKSON More no nonsense books from no starch press STEAL THIS COMPUTER BOOK 1 0 What They Won t Tell You About the Internet by WALLACE WANG This offbeat non technical book examines what hackers do how they do it and how readers can protect themselves Informative irreverent and enter taining the completely revised fourth edition o
288. ooking at the status lights on the modem router or switch You won t need this phone very often but when something goes wrong you will be happy to have it Use a cell phone ora cordless handset if you have one or install an inexpensive wall phone on or near the control panel If possible look for a simple desk or wall phone that does not require an external power supply Tabletop Control Centers for Small Networks You don t need a separate control center for a small network that connects computers in just a few rooms It s often easier to place the modem and router in one room and run data cables directly to each of the other rooms You can place the modem and router on your computer table or on a nearby bookshelf Leviton and other manufacturers make wall plates that can hold up to six or eight data outlets in the same space as a dual AC outlet That should be enough for a small network if you need more add a second wall plate or replace the first one with a dual width plate When it s time to expand your network you have two options You can run new wiring from the original control room to the new location or you can add a downstream switch in the room closest to the location and run a Installing the Network Control Center and Ethernet Cables 67 68 NOTE Chapter 6 data cable from there The second approach can be particularly convenient when the new location shares a wall with a room that already has a data outlet
289. op Access To configure a Windows XP computer to accept Remote Desktop access follow these steps l Right click My Computer A pop up menu will appear 2 Select Properties from the menu The System Properties window will open 3 Click the Remote tab The dialog shown in Figure 16 1 will appear System Properties 3 x General ComputerName Hardware Advanced System Restore Automatic Updates Remote 5 Select the ways that this computer can be used from another location r Remote Assistance Allow Remote Assistance invitations to be sent from this computer hat is Remote Assistance ry Remote Desktop Allow users to connect remotely to this computer Full computer name tower What is Ramote Desktop Select Remote Users For users to connect remotely to this computer the user account must have a password Windows Firewall will be confiqured to allow Remote Desktop connections to this computer 9 se oe Figure 16 1 The Remote tab in System Properties controls inbound and outbound access to the Windows Remote Desktop utility 4 Touse this computer to control other computers remotely on your net work check the Allow Remote Assistance invitations option in the Remote Assistance area 5 To permit another computer on your network to take control of this computer check the Allow users to connect remotely option 6 When Allow users to connect remotely to this computer is tu
290. or DVI connector on your computer If your video controller doesn t have an extra video output install another video controller card in an empty expansion slot Don t worry about high performance and memory unless you re playing bleeding edge games you can use an old PCI video card with as little as 8 or 16 MB of memory from your junk box or a second hand computer store None of this requires MaxiVista You can use the Display Properties controls in Windows to extend your desktop to additional monitor screens But if you want to use a laptop computer as your second screen or if you already have two or more networked computers on the same table or countertop MaxiVista allows you to use the monitors on those additional computers as extended screens and switch back to normal use when that s more convenient If you already have both a laptop and a desktop computer MaxiVista allows you to try an extended screen without the need to haul out any extra hardware just plug your laptop into the network install the free trial version of MaxiVista and reconfigure your Display Properties settings as shown in Figure 16 5 Display Properties 2 x Drag the monitor icons to match the physical arrangement of your monitors Display 2 Radius RADS on RADEON 9600 SERIES Secondary Screen resolution Color quality less J More Highest 32 bit 7 1024 by 768 prets E E NES E Use this device as the primary monitor v Extend
291. or if you re a slave to fashionable footwear you can think of it as Oxfordnet or Slingbacknet or Espadrillenet instead Whatever you choose to call it physically carrying files from one place to another is often a distracting time consuming nuisance However sneakernet does have its uses When you travel it can often be easier and more convenient to carry a few files with you rather than retrieve them from a distant computer through the Internet If you plan to use com puters in two or more locations such as one at school and another at home you might be better off storing the file on a small portable drive instead of hauling your laptop around When security is an important issue you might not want to connect your computer to any network The very best way to protect your confidential data from theft through a network is to make sure the computer where the data is stored has no network access Sneakernet is not always the slowest way to move data from one computer to another If you want to move a lot of data over a relatively short distance when you don t have a high speed data connection it can often be faster to drive a handful of DVDs or a box of tapes across town than to send the same files through a dial up connection or any other slow network link It s one of the oldest maxims in the world of computers and networks but it s still true Never underestimate the bandwidth of a station wagon full of floppy disks
292. or low cost email services such as Hotmail Gmail or any of the others described at hitp www emailaddresses com Adding one or more file servers to a network to share resources goes a long way toward increasing the value of your computers You can certainly operate your small network without any servers but like the network itself a central storage location for documents images and other files is often a lot more convenient than storing everything on individual users machines especially if you can use an old computer as a server that would otherwise continue to collect dust in a storage closet File Servers 105 CONNECTING YOUR NETWORK TO THE INTERNET network file sharing internal web hosting and so forth are handy but the main reason that most people want to connect all of their household computers together is to share a high speed Internet connection In a business those other services are more important than they are at home but Internet access for everybody is still important This chapter explains how to connect a net work to the Internet and how to set up each computer to connect to the Internet through the network The Internet is often described as a network of networks In other words the Internet provides a way to exchange data between your own LAN and millions of other networks Before you can exchange data between your local network and the Internet however you or your network manager must
293. ored on the computer even if you never sent that data over the wireless network This type of attack might be relatively rare casual snoopers are unlikely to take the time to snoop around on the chance you have some thing interesting but it still presents a real risk Also many popular websites encrypt the login page with SSL encryption via HTTPS but they don t encrypt subsequent pages to reduce the drain on processing power your password might be secure but any email you read via the web mail interface might not be and attackers might be able to steal the cookie a unique piece of data passed with web data that identifies your login and open your mailbox directly Protecting Your Network and Your Data As the operator of a Wi Fi network what can you do to keep outsiders out You can employ a few techniques that can discourage them First you can accept the fact that wireless networks are not completely secure and use the built in network security features to slow down would be intruders second you can supplement your wireless router s built in tools with a hardware or software firewall or both to isolate the wireless network and third you can use additional encryption such as a VPN to secure traffic to the network The security features of the early Wi Fi protocols WEP encryption were not adequate to protect data The wireless equivalent privacy WEP protocol had several serious flaws The basic encryption method the RC4 a
294. orks security selective backups 100 serial data communications channels 11 Series2 Dual Tuner DVRs 216 Single Tuner DVRs 216 Series3 HD DVRs 216 Server Message Block SMB protocol 131 143 145 147 146 150 servers See also file servers 2X Terminal Server 226 Apache web server 95 156 audio music 7 8 207 209 212 213 213 audiophile music 209 client and server structures 23 25 25 computer for 94 DHCP 38 109 115 111 112 117 118 124 126 126 129 157 158 163 DNS 40 41 42 43 44 109 115 118 124 127 246 file storage 24 96 97 file transfer 39 firewall 24 game 24 HTTP web 158 internal external printer 192 192 193 mail 24 message 234 printer 7 25 25 193 197 Public DNS 41 root 40 stereo component music 208 types of 24 25 25 USB device 99 99 100 video 7 8 215 VPN 161 162 165 165 167 169 168 Windows Home Server 95 96 96 208 215 server side backup programs 104 Service Set Identifiers SSIDs 86 90 177 179 178 183 244 283 shared directories 150 shared folders 5 139 141 150 shared Internet connections 6 Shared Key Security field 180 shared printers 7 143 196 196 199 198 199 shares 139 sharing permissions 96 97 97 shoulder surfing 184 Silex Technology 99 Simple File Sharing 132 132 133 136 Slim Devices 213 214 214 smart home appliances 223 SMB Server Message Block protocol 131 143 145 147 146 150 SMTP outgoing m
295. ormation in a particular format For example web browsers such as Firefox Opera and Internet Explorer are all clients that use the HTTP HyperText Transfer Protocol commands specified by the World Wide Web Consortium every web server in the world recognizes those commands A client and server are not always connected to the same LAN some times they connect through the Internet or through a large corporate WAN Wide Area Network For example when you download a page from a website or a music file from a service such as iTunes or Zune you re using your own computer as a client to obtain something from a web server A network can take advantage of many kinds of clients and servers Here are just a few Mail server A computer that handles inbound and outbound mail for all network users File server A computer that stores data files and makes them available through any computer connected to the network Music server A specialized file server that stores music files and makes them available to computers and home entertainment systems Firewall server A computer that acts as a security firewall between the other computers on the network and the rest of the world Game server A computer that acts as host for a multiplayer game A server can be a separate computer that runs only specialized server software a general purpose computer that runs server programs along with other programs or an even more specialized device that contains a special
296. osoft introduced a completely new file sharing method in Windows Vista It s still necessary to turn on file sharing but the whole process is no longer as complicated as the earlier Simple File Sharing method because many of the network file sharing functions are consolidated into the Network and Sharing Center shown in Figure 12 4 To open the Network and Sharing Center start at the Control Panel and select Network and Internet gt Net work and Sharing Center If you re using the Classic View of the Control Panel you can go directly to the Network and Sharing Center QU amp gt Control Panel Network and Sharing Center 491 Search File Edit View Tools Help Network and Sharing Center View full map B a va TOWER Internet This computer Wis Local Private network Customize Access Local and Internet Connection Local Area Connection View status Sharing and Discovery Network discovery File sharing Public folder sharing Printer sharing Password protected sharing Media sharing On Show me all the files and folders am sharing See also Internet Options Windows Firewall Show me all the shared network folders on this computer Figure 12 4 The Network and Sharing Center controls many file sharing functions Network Discovery One important new setting in Vista is called network discovery When network discovery is turned on your computer is visible to other computers on the same LAN an
297. ou connect a terminal to a control device the output pins on the DTE device connect to the input pins on the DCE device The problem arises when you want to connect two computers without a control device in between Direct computer to computer communication requires a special cable because you can t connect a DTE device directly to another DTE device When you connect two DTE devices with serial data ports you connect the output on one computer to the output on the other computer and the input to the input so neither computer will actually receive any data Therefore you must flip the connections so each output connects to an input A cable or adapter that connects output pins to input pins is called a null modem Figure 2 6 shows a typical null modem adapter pe te nek ih TT Figure 2 6 A null modem adapter or cable connects inputs directly to outputs NOTE The data moves in only one direction rule does not apply to data moving through coaxial cable which can handle inbound and outbound signals modulated at different frequencies through the same cable Point to Point Networks Most of the time we think of a computer network as a structure that can link one computer to any other computer connected to the same network But sometimes all you need is a direct connection between two computers This kind of connection is called a point to point network Figure 2 7 shows both network types A point to point connection is handy w
298. ou enter into a network device must be exactly the same as the one stored in the access point Obviously typing 64 digits correctly is not something that you want to do frequently so the ASCII alternative is the better choice for most users For optimal security the ASCII passphrase you assign to your network should be a random mixture of at least 20 characters including letters capitals and lowercase numbers and punctuation marks A PSK network uses the passphrase to set up the initial connection between a client such as a computer or PDA and the access point After the connection is in place the TKIP assigns new encryption keys to every packet or group of packets The PSK combines with your network SSID to calculate the final key value Choosing a unique SSID and a strong passphrase is important Attackers can build large tables of SSID and PSK pairs for common network names and dictionary words performing weeks of calculation once with the payoff of nearly instantly determining the key of any network that matches that pair of values Choosing strong passphrases and unique SSIDs can mitigate this attack Using WPA Encryption When you set up a new network the security section of the access point s configuration software will ask if you want to use encryption and if so whether you want WEP or WPA encryption Unless you re planning to run an open access network you should choose WPA In many cases the access point will offer
299. ou need updates for Windows your programs your hardware or Merge spk acyl is your devices set to receive e tea security amp critical Express Get high priority updates updates Restore hidden recommended automatically updates Pick a time to Change settings Custom Select from optional and install updates FAQ high priority updates for Windows and other Get help and programs support Concerned about privacy When you check for updates basic information about Use your computer not you is used to determine which updates your programs need administrator To learn more see our privacy statement Microsoft Update Privacy Statement 2008 Microsoft Corporation All rights reserved Terms of Use Trademarks Privacy L Done T T T T T inteme Figure 13 20 Use the Custom button to search for nonessential updates After the program completes its search for new programs it will display a list like the one shown in Figure 13 21 Use the list of update types in the left column to display a list of available updates in each category Don t forget to scroll down the list to see all the categories Microsoft ANN Windows Internet Ee jslx vir x Aje Q ER EHE Quick Links Home Worldwide 4 Search Microsoft com for Go Microsoft CustomzexouLresulu LL C C C CC A Update Home PLAN da Select High Priority Updates Install To help protect
300. p with a video stream and even a wired 100 BaseT network might overload if you try to push through more than one video stream at the same time When you want to download a movie or some other large video file through the Internet it s often better to save the file to your computer s hard drive rather than trying to view it as the computer receives it because the download speed is often too slow for the video player program to assemble the digital packets and display them as a continuous stream On the other hand when all the bits are already on a DVD or hard drive the video player can play the stream without the need to wait for more bits to arrive You can think of the stream of incoming bits as a garden hose that fills a watering pail with a slow trickle of water if you pour out water more quickly than the hose fills the pail you must refill the pail before you can pour more water The same thing applies to video files through a network If the data packets that contain the video stream enter your network more slowly than the video player assembles and displays them the player s buffer will run out of bits and stop displaying anything until it receives more Video Servers A video server is a network server that stores movies and other video files and sends them through the network to video player programs on client computers or video players Most video servers can also store and distribute music files Some computer operating system
301. printed and bound at Malloy Incorporated in Ann Arbor Michigan The paper is Glatfelter Spring Forge 60 Antique Eggshell which is certified by the Sustainable Forestry Initiative SFI The book uses a RepKover binding which allows it to lay flat when open UPDATES Visit hitp www nostarch com networks him for updates errata and other information OLLI ULLAL RE MADE PAINLESS m 3 T n NN Are the machines in your office living isolated lives Do you have a few computers at home that you want to connect to each other and the Internet The best way to share files on a group of computers is to create a network But how do you do that Network Know How is your guide to connecting your machines filled with practical advice that will show you how to get things done You ll learn the nitty gritty of network setup design and maintenance from running cables and placing wireless access points to configuring file sharing and printing This practical and comprehensive guide will teach you how to implement security create intranets and more You ll learn how to Connect Windows Macintosh and Linux computers Implement network addressing Configure your network adapters hubs switches and router e Share music photos and documents no starch press ISBN 978 1 59327 191 6 n 781593 271916 il Automate household appliances and distribute digital audio and video to your home entertainment
302. ption shown in Figure 10 2 must be active Internet Protocol TCP IP PF x General Alternate Configuration You can get IP settings assigned automatically if your network supports this capability Otherwise you need to ask your network administrator for the appropriate IP settings Obtain an IP address automatically C Use the following IP address C Obtain DNS server address automatically amp Use the following DNS server addresses Preferred DNS server 198 137 231 1 Alternate DNS server 206 63 63 1 Figure 10 2 When the Obtain an IP address automatically option is active Windows uses the network s DHCP server to set its IP address In Macintosh OS X the Configure IPv4 option shown in Figure 10 3 must be set to Using DHCP e The IP address number assigned by the DHCP server must be within one of the reserved ranges In almost all cases you don t have to change the server s default values Most hubs routers modems and Wi Fi access points use one or more web based pages such as the one shown in Figure 10 4 to display and change the DHCP server s settings However the pages supplied with just about every make and model of network control device are organized slightly differently So you must consult the manual supplied with your device or the manufacturer s website for specific instructions Connecting Your Network to the Internet TH 112 Chapter 10 60 Network xo
303. r The port type must be set to the correct VPN protocol for example PPTP or L2TP and the profile for each connection must include the type of encryption in use Windows offers three encryption strength options Basic Uses a 40 bit encryption key Strong Uses a 56 bit encryption key Strongest Uses a 128 bit encryption key VPN Servers for Linux Unix All of the BSD variations including FreeBSD NetBSD OpenBSD and Mac OS X include an IPsec VPN client and server as part of the release package Linux FreeS WAN is the most popular implementation of IPsec for Linux Go to hitp www freeswan org for downloads documentation and access to the community of FreeS WAN users OpenVPN is an SSL based VPN solution for Linux BSD OS X and Windows OpenVPN is easy to configure and offers both routed VPN traffic to specific destinations is sent through the VPN and tunneled virtual interfaces emulating a physical layer Ethernet device which can pass non IP traffic through the VPN OpenVPN can be found at Attp openvpn net If you re using a Linux firewall you might want to consider VPN Masquerade Linux uses the IP Masquerade function in the Linux kernel to share a single connection to the Internet among multiple clients VPN Masquerade is the section of IP Masquerade that supports IPsec clients The HOWTO for Linux VPN Masquerade is at hitp tldp org HOWTO VPNMasquerade HOWTO html Network Hardware with Built In VPN Support A dedica
304. r causing hardware to break down Two important objectives of network security are to limit access to author ized users and to keep those same users away from configuration settings and confidential data The most important tools for maintaining a secure network include different access levels for different users passwords and firewalls If they re not adequate more complex methods are also possible including kernel level mandatory access control systems authentication and authoriza tion mechanisms and data encryption User Accounts and Access Levels Almost all computer operating systems have at least two levels of user accounts administrators and users Administrators have access to all of the computer s configuration settings such as installing or removing printers joining a net work and so forth Users can read and write programs and data files assigned to their own accounts and to resources whose owners allow other people to use them On a network a guest account has its own access settings for those who use a computer s resources through the network rather than through the keyboard and other input devices connected directly to each computer Each user has exclusive control of his or her files The owner of every account can set access controls on files that keep them either private and confidential or public and accessible to other users Even if other users have accounts on the same computer they can t read somebody else
305. r existing password or a new password and click the Save button 7 Confirm that you can now log in to the Mac from another computer connected to the network If it works the process is complete 8 Ifyou can t log in to the Mac from another computer try changing the user s password Setting the Workgroup Name Each computer on the network should use the same SMB workgroup name but the default in Mac OS X is WORKGROUP which is probably not the name your Windows network uses To change the workgroup name on a Mac follow these steps 1 Select Applications gt Utilities Directory Access 2 Click the padlock icon to identify yourself as an administrator 3 Select SMB CIFS from the list of services as shown in Figure 12 13 eoo Directory Access f Services Authentication Contacts Enable Name Version Active Directory 1 5 8 M AppleTalk 1 2 v Bonjour 1 2 Lj BSD Flat File and NIS 1 2 2 m LDAPv3 1 7 4 LJ Netlnfo 1 7 4 M sip 1 3 1 Configure J 3 Click the lock to prevent further changes Revert Apply Figure 12 13 Select SMB CIFS from the list of services 4 Select Configure The program will scan the network and display a list of workgroups On most small networks you will see only one workgroup name 5 Select the workgroup name you want to use and click OK Click Apply and quit Directory Access Sharing Files Through Your Network 145 146 Chapter 12 Turning on Windows File
306. r has a built in Ethernet port the driver software that instructs the central processor how to handle network data is on the software disc supplied with the computer or the motherboard If your computer came with the operating system already installed the driver is already in place However if you assemble your own computer from parts you might have to install the network driver supplied with the motherboard or a third party after you load the Windows Linux or Unix operating system Figure 7 2 Most new computers come with Ethernet ports as standard features Setting the BIOS Utility If your computer has a built in Ethernet interface it s sometimes necessary to turn off that interface and use a network adapter on an expansion card or some other kind of external network interface This might happen when you want to use a faster network than your built in adapter can handle such as a Gigabit Ethernet network or if the onboard network controller doesn t work correctly To turn off the internal network interface you must open the computer s BIOS settings utility and find the option that enables or disables the onboard LAN controller or some other option with a similar name In most BIOS utilities the LAN option is buried under two or three menu levels The BIOS settings utility is a set of controls that load configuration settings when you turn on the computer These settings are an essential part of the computer s startup seque
307. r that identifies the type of server For example web servers operate on port 80 and FTP servers use port 21 so those port numbers are part of the request for access To accept access requests to a server you must instruct the firewall s Network Address Translation NAT function to forward those requests to a specific computer within the LAN Table 13 2 lists the most common service port numbers Hundreds of other port numbers have been assigned but you will never see most of them in actual use The official list of port assignments is available online at hitp www iana org assignments port numbers NAT assumes that each internal server s IP address doesn t change from one request to the next A web server on 192 168 0 23 today won t migrate to 192 168 0 47 next week That s generally not a problem on a wired network but in a wireless setting where network clients join and leave the network all the time the DHCP server automatically assigns the next available address to each new client If one of those clients is the home of one of the network s Network Security 157 158 Chapter 13 service ports the NAT probably won t find it This problem is not common because most networks don t use portable computers as servers but it can happen The solution is to turn off the DHCP server and assign a permanent IP address to each client Table 13 2 Common TCP IP Service Port Numbers Port Number Internet Service 20 FTP Data
308. rands of equipment in the same network Today more than 85 percent of all local area networks LANs including just about every modern home and office network use some form of Ethernet to provide the physical connection between computers through twisted pair cables coaxial cables or fiber optic cables One of Ethernet s most important features is the method it uses to prevent conflicts among nodes called Carrier Sense Multiple Access with Collision Detection CSMA CD Every time a network node is ready to transmit a frame it checks if another frame is already using the network if the network is clear the node sends the frame But if the node detects that another frame is using the net work a condition called a collision it waits a random period of time before it tries again CSMA CD is important because it allows a relatively large number of computers and other devices to operate through the same network without interference There are many Ethernet specifications that cover different data transfer speeds and different kinds of cables and connectors The ones you re most likely to see in a small LAN include the following e 10Base T 10 Mbps through twisted pair cables e 100Base T or Fast Ethernet 100 Mbps through twisted pair cables e l000Base T or Gigabit Ethernet 1000 Mbps through twisted pair or fiber optic cables e Wireless or Wi Fi any of several systems that use radio signals instead of wires the latest 802 11n Wi Fi
309. rate the computer On some computers the LINK and 10 100 lights might remain on when the computer is turned off This happens when the computer s BIOS has a wake on LAN feature that turns on the computer if the adapter receives an incoming signal Even if this feature is disabled the computer keeps the network port alive whenever the power supply is turned on The only way to disable the network adapter completely is to either unplug the AC power or turn off the power switch on the back of the power supply Ethernet Network Interfaces 75 WI FI NETWORKS Wi Fi short for Wireless Fidelity pro nounced why fie networks use radio signals instead of Ethernet cables to connect computers and other devices to a LAN Wi Fi is a convenient alternative to conventional wired networks because any wireless enabled computer within range of the Wi Fi signal can join the network there s no need to find a network outlet This can be particularly useful when it s not practical to pull data cables through walls ceilings and floors and when a user wants to connect a laptop computer or a handheld device such as an iPhone or BlackBerry to an existing network or through a LAN to the Internet And of course thousands of Wi Fi hotspots in public spaces such as airports coffee shops libraries and schools offer easy access to the Internet when you re away from your own home or office However Wi Fi connections are far less secure than wired
310. rd compatible with 64 bit encryption but compatibility is not auto matic so all of the devices on a mixed network of 128 bit and 64 bit devices will operate at 64 bits If your access point and all of your adapters accept 128 bit encryption use a 128 bit key But if you want your network to be com patible with adapters and access points that only recognize 64 bit encryption set the entire network to use 64 bit keys In practice the choice of 64 or 128 bit WEP encryption doesn t make much difference Tools are easily available that can crack both types although cracking a 128 bit key might take a bit longer Is Your Key ASCII or Hex The length of the key is not the only confusing thing about setting WEP encryption Some programs request the key as a string of ASCII characters but many others want the key in hexadecimal hex numbers Still others can generate the key from an optional passphrase Each ASCII character has 8 bits so a 40 bit or 64 bit WEP key contains 5 characters and a 104 bit or 128 bit key has 13 characters In hex each character uses 4 bits so a 40 bit key has 10 hex characters and a 128 bit key has 26 characters In Figure 13 18 the Wireless Setting screen for a D Link access point the 40 bit Shared Key Security field uses hex characters so it has space for 10 characters The D Link program runs all 10 characters together in asingle string but some others split them into 5 sets of 2 digits or 2 sets of 5 Th
311. rds they grab each block of data a frame as it passes in or out of your computer and they display the contents of the frame along with detailed information about the form and structure of each frame Figure 17 3 shows a data capture in Network Monitor and Figure 17 4 shows a Wireshark screen The two programs capture the same data stream but they handle and display it differently The programs are available at no cost so you might want to install both of them Protocol analyzers are also known as network sniffers 3 Network Magic Pro My Network File View Tools Help Figure 17 2 Network Magic scans your LAN and displays all the devices connected to it Most of this data display looks like hexadecimal gibberish but it contains the actual text of messages conversations and other transactions along with all the commands and status messages that move through the network Most of the time you can allow your computer and the network plumbing to handle the data in background But when something goes wrong the data captured by a protocol analyzer can help you identify what s causing the problem For example if the amount of incoming or outgoing traffic moving through your network increases the network may be sending or receiving many requests every second This could be a hacker s denial of service attack or a computer that has innocently latched itself into an endless program loop Either way you will want to identify the source
312. re 14 4 Use the Sharing tab of the printer s Properties dialog to turn on sharing 4 In Windows XP select the Share this printer option In Vista click the Change sharing options button click Continue in the User Account Control window and then select Share this printer 5 In the Share name field type a name that identifies this printer such as Don s Printer In Windows Vista the Sharing tab includes an option to render print jobs on client computers If the other computers on the network use Windows XP or some other operating system leave this option turned off But if other Vista computers will be sending print jobs to this printer you can speed up the printer s performance by checking this option Installing the Printer on Each Computer After you set up the computer acting as a printer server to accept print jobs through your network you must also add the server to each computer s list of printers Follow these steps to add a network printer in Windows XP 1 From the Control Panel select Printers and Faxes The Printers window will open 2 Double click Add a Printer to open the Add Printer Wizard The Welcome screen will appear 3 Click Next The Local or Network Printer screen will appear Printers and Other Devices on Your Network 197 198 Chapter 14 4 Select the network printer option and click Next The Browse for Printer screen shown in Figure 14 5 will appear along with a list of shared printers co
313. re flexible and powerful than the individual computers connected to it As you plan a new network or expand the one you already have you should think about each network activity as either a client program that runs on local computers or a server that supplies the program from a central source Types of Network Connections 23 24 NOTE Chapter 2 It s important to understand that a server is not always a dedicated computer in many small networks one or more server programs run on the same computer that is also used by one of the network s users for day to day activity For example if you store your entire collection of music files on one computer and play those files from other computers connected to it through your network the computer that contains all the files is a storage server and each of the players is a client Or if you print documents by sending them to another computer or a stand alone printer through the network the computer or the special network node device that controls the printer is a printer server A server almost always communicates with users that s you and me through a client It s rare for anybody except the system manager or main tenance people to work directly with a server program The software that sends instructions to a server and receives data or other services is a client program Each server communicates with a client program that sends it the correct set of requests and receives inf
314. rectly on a wall like the ones shown in Figure 6 7 When you mount a device on a wall panel place it below eye level with the front panel at the top of the box so the status lights are easy to see If there is no allowance for mounting holes on your modem switch or router and you re using a wall mounted control center attach a 6 inch shelf to the plywood panel and place the devices on that shelf If you re using a modular structured wiring center there s usually space at the bottom of the cabinet that you can use as a shelf For a rack mounted control center use a rack shelf for any devices that don t mount directly into the rack Installing the Network Control Center and Ethernet Cables 63 64 Chapter 6 Model DSS 5 DLink H W Verst cE S N WHEE CONN B20533C 008920 d Figure 6 7 This D Link switch has keyhole slots on the bottom of its case Use big wire staples from the hardware store to route the power cables neatly along one side of your control panel between each control device and the power strip Don t mash the staples all the way into the plywood allow some space to be sure you haven t crushed any of the wires Be sure to leave enough slack wire at the back of each device to allow yourself to unplug the power connector easily Adding a DSL or Cable Connection Broadband Internet service comes into your building through either a tele phone line or a TV cable Therefore you will need either a teleph
315. rer 24 174 Internet Protocol IP 35 36 54 123 123 126 addresses 36 41 36 42 45 86 computer to network connections and 118 124 126 128 127 domain names and 38 41 40 dynamic 37 38 86 109 firewalls and 157 fixed 37 38 109 118 network to Internet connections and 110 115 111 112 filters 159 networks 162 Internet Protocol Properties window 123 Internet radio 209 214 Internet Relay Chat IRC servers 39 Internet service providers ISPs 22 31 41 110 113 114 problems 251 Internet to network connections 6 107 115 108 111 112 I O input output ports 4 18 18 19 19 IP See Internet Protocol IP IPConfig 41 43 42 iPhone 77 IP Masquerade 164 iPod 8 206 207 210 IPsec network links 162 163 164 169 173 IPX networks 162 IRC Internet Relay Chat servers 39 IrDA See Infrared Data Association IrDA ISA Ethernet adapters 72 INDEX 257 258 INDEX ISM bands 80 ISPs See Internet service providers ISPs iTunes 24 J Jabber 235 jacks See ports Jameco 57 jumper cables 56 K Kaspersky Online Scanner 245 KDE 104 128 128 129 129 148 148 149 Kerberos 158 keyhole slots 63 64 64 Konquerer file manager 148 746 149 150 150 L L2TP Layer Two Tunneling Protocol 162 163 164 169 LANguard 158 LANs See local area networks LANs Lantronix UBox 4100 99 laptops interface adapters 81 82 82 network adapters 73 74 74 Laughing Squid web
316. ress of the device that assigns IP addresses to other devices on the LAN in this case this device is the same as the Default Gateway and the DNS Servers are the computers that this network consults to convert DNS addresses into numeric IP addresses The Lease Obtained and Lease Expires lines show the date and time that this computer obtained its IP address from the DHCP server and the time the computer will give up that address the host automatically renews the lease long before it expires so you don t have to worry about the expiry time ifcontig The ifconfig command is available in Macinstosh OS X and in Unix and Linux This command displays information about the current network interface including the connection type and the connection s current status The format of the information display however varies in different operating systems Therefore the best place to find a detailed explanation of the ifconfig display produced by your own system is the man page for the ifconfig command ping The ping command is an echo request When you type ping target address your computer sends a series of please answer messages to the target address and that computer sends you a reply as shown in Listing 4 3 Your computer measures the amount of time for each roundtrip and displays the duration in milliseconds C gt ping nostarch com Pinging nostarch com 72 32 92 4 with 32 bytes of data Reply from 72 32 92 4 bytes 32 time
317. ring the WAN side of a modem router or other network control device is in the information provided by your ISP Specifically when you set up a new ISP account you should obtain your connection s static IP address or DHCP setting the DNS server addresses the subnet mask and the gateway address The ISP will probably give you addresses and a password for your email account at the same time but you don t need them to configure the network connection although you will need them to send and receive messages If your ISP requires a login and password every time you connect you will need a router or modem that uses the same set of connection rules the protocol that your ISP s equipment expects If your ISP does not provide a modem ask them for a list of compatible makes and models The LAN side of the router uses addresses and other settings that don t extend beyond your own network so your network can use the same settings as your neighbor s network Therefore many manufacturers ship their routers with preset addresses that should work for most networks The user s manual or setup guide supplied with the device usually contains step by step instruc tions for changing the settings If you can t find a printed copy of the manual look for one on the manufacturer s website NOTE Chapter 11 contains detailed instructions for connecting routers using Windows Mac intosh OS X and Linux or Unix to a LAN To connect a NAS device p
318. rinter or other device to the network follow the instructions supplied with each device Summary Your network connects to the Internet through a gateway router that appears as a node on both your own LAN and your ISP s WAN In order to exchange data between a network computer and the Internet you must configure the WAN side of the router with addresses and options supplied by your ISP The LAN side of the router controls the way your own network handles communication with the Internet Therefore the router s LAN side settings must be compatible with the settings on each computer and other device connected to the LAN Connecting Your Network to the Internet 115 CONNECTING YOUR COMPUTER TO A NETWORK a computer uses it requires the same configuration settings to connect to a LAN and to the Internet Each operating system organizes configuration information differently but they all require the settings described in Chapter 10 This chapter describes the configuration settings for Windows Macintosh OS X and for Linux and Unix and it offers step by step instructions for connecting computers running those operating systems to your network Before you try to configure the computers in your network set up the LAN and WAN settings on the network s modem and router the configura tion of your network s computers must be compatible with those settings If your network includes an active DHCP server your computer should automatica
319. rinter for routine documents and reports a color inkjet or laser printer for fancy presentations and school projects and a special purpose color printer for digital photos If you have more than one printer you can select the best printer for each job Each of these printers might be located in a different room close to the person who uses it most often or in a central room where they re equally accessible to all of your network s users 192 How to Connect a Printer to Your Network NOTE Chapter 14 You can connect a printer to a network in several ways You can use an external printer server a server built in to your printer or an automatic switch connected directly to each printer or you can connect through a computer All of these methods accomplish the same thing They send a formatted document or image to a printer that produces a paper copy The best method for connecting a printer to your network depends on your budget what s convenient for you and the layout of your network External Printer Servers An external network printer server is a device that connects to the network as a separate network node with an Ethernet port and provides either a parallel port connection or a USB connection to a stand alone printer Figure 14 1 shows a printer connected to a network through an external printer server Desktop computer Desktop computer Router Server Figure 14 1 An external printer server connect
320. riously flawed PPTP The server also requires two network interface cards one connected to the wired LAN or the Internet gateway and the other connected to the wireless network The interface card that is connected to the wireless port normally connects directly to the wireless access point s Ethernet port The exact process of installing an L2TP host on a Windows server is slightly different in each version of Windows but the general steps are the same For specific information about configuring a particular operating system consult the online Help screens and Microsoft s Resource Kit and other online documentation for your server s operating system The following sections describe the configuration steps in general terms For more information about deploying and using VPNs with Microsoft servers see the Microsoft TechNet articles at http technet microsoft com en us network bb545442 aspx Configure the connection to the LAN The link to the LAN or other network is a dedicated connection through a network adapter The network connection profile for this connection must include the IP address and subnet mask assigned to this connection and the default gateway address assigned to the network gateway Configure the VPN connection The VPN connection is usually an Ethernet link to one or more access points The connection profile on the server for the VPN connection must include the IP address and subnet mask assigned to this port and th
321. rk access point which the operating system sees as a LAN connection To set up a VPN tunnel through that connection you must install the tunneling protocol as a network service Configuring Windows for VPN Windows XP and Vista include support for virtual private networks but this support is not part of the default installation so the first step in setting up a VPN client is to install the protocol In Windows XP and Windows Vista a wizard makes the whole process easy In XP follow these steps to set up a VPN connection From the Control Panel open Network Connections Double click the New Connection Wizard icon When the Network Connection Type window shown in Figure 13 6 appears select the Connect to the network at my workplace option and click the Next button Network Security 165 166 Chapter 13 New Connection Wizard Network Connection Type What do you want to do Figure 13 6 The option for creating a VPN link specifies connecting to a workplace network but this option also applies to a wireless VPN In the Network Connection window shown in Figure 13 7 select the Virtual Private Network connection option and click the Next button New Connection Wizard Network Connection How do you wantto connectto the network at your workplace Figure 13 7 Select the Virtual Private Network connection option to create a VPN connection In the Connection Name window type a name for the wireless VPN
322. rned on anybody who is logged on to another machine on the same network with the same username as an Administrator account on this computer and who uses a password to log into this computer can request remote access To allow a non Administrator to use Remote Access click the Select Remote Users button click the Add button in the Remote Desktop Users window and then type the account name for the person who you want to allow to use Remote Access 7 Clickthe OK buttons in each of the open windows to save your data and close the windows To configure Windows Vista for Remote Assistance follow these steps Right click My Computer The System window will appear 2 Click Remote settings in the Tasks list on the right side of the window The System Properties window will appear with the Remote tab visible as shown in Figure 16 2 Other Network Applications 227 228 Chapter 16 4 System Properties Computer Name Hardware Advanced System Protection Remote Q Select the ways that this computer can be used from another locabon Remote Assistance Allow Remote Assistance connections to this computer What happens when enable Remote Assistance Figure 16 2 Use the Remote tab in System Properties to turn Remote Assistance on or off Check the Allow Remote Assistance connections to this computer option Activating this option will allow both inbound and outbound remote access Click OK to save your sett
323. roller automatically moves on to the next row when it reaches the end of the bottom row the controller returns to the top At some point in the signal chain the analog image from the camera s lens converts to a continuous digital data stream in most cases this occurs inside the camera itself but some equipment might perform the analog to digital conversion in the controller card As an alternative a camera captures still images one at a time and stores them or transmits them through the network as a series of image files Many camera controller cards include two or more camera inputs In general a multiple input card costs more than a single input card with similar image quality and performance The computer can use a sound card or a USB or FireWire port to handle audio in a similar manner The sound card accepts analog audio directly from a microphone or through an external amplifier mixing desk or other source the USB port receives digital audio from an external analog to digital converter After the computer receives one or more video streams audio streams or still pictures it can do the following e Store them on a hard drive or other mass storage device e Display the pictures on the computer s video monitor as live images e Play the sound stream through the computer s speakers or through headphones plugged into the computer e Incorporate them into another program or document such as a web page or a word process
324. rosoft distributes security updates and patches through the Internet at least once every month that include fixes for newly discovered security problems You can manually check for updates and select the ones that you want to install but it s a lot easier to let Windows automatically check for newly released update packages and install them for you As network manager you will want to set all the Windows computers on your network to run Automatic Updates Network Security 185 To run Automatic Updates follow these steps 1 Right click My Computer and select Properties from the pop up menu The System Properties window will appear 2 Choose the Automatic Updates tab from the System Properties window The dialog shown in Figure 13 19 will appear axi General ComputerName Hardware Advanced System Restore Automatic Updates Remote Windows can reqularty check for important updates and install them for you Turning on Automatic Updates may automatically update Windows Update software first before any other updates How does Automatic Updates work Automatic recommended Automatically download recommended updates for my computer and install them Every day at 200PM C Download updates for me but let me choose when to install them C Notify me but don t automatically download or install them C Tum off Automatic Updates Your computer will be more vulnerable unless you install updates regularly Figure
325. rses and spyware on each computer connected to your LAN Even if you have firewalls up to date antivirus programs and other network security software running on all your computers it s possible that something might have slipped through your defenses Several antivirus program vendors offer free online scans that might identify a virus that your resident program might not catch As part of your troubleshooting routine run a full scan with your usual network security programs and also use one or more of these online scans Trend Micro HouseCall Attp housecall trendmicro com Symantec Security Check Attp security symantec com sscu6 defaullt asp BitDefender Online Scanner Attp wwuw bitdefender com scan6 ie html Kaspersky Online Scanner http www kaspersky com virusscanner ESET Online Scanner itp www eset com onlinescan Panda ActiveScan Aitp www pandasecurily com homeusers solutions activescan Use an online scanner made by a different supplier from the one that came with the antivirus program resident in your computers Each company employs a slightly different set of rules for finding and isolating viruses so you will want to take advantage of more than one approach Other Common Problems It s not practical to describe every possible network problem but there are a few that occur more frequently than others If the problem in your network is not described in this chapter try the Windows Network Problem S
326. rvers as possible But if you can t obtain reliable DNS service from your local service provider a public DNS is often a useful alternative You can find addresses for several public DNS servers though a Google or other web search for Public DNS server Some public DNS services can also provide some added features that your ISP might not offer For example OpenDNS hitp www opendns com can provide another layer of filtering against spyware identity theft adult sites and other possible problems It will also allow you to set up two three letter shortcuts to frequently used addresses and will automatically correct common keystroke errors such as typing example cmo instead of com There s some controversy about some of these features because they could lend themselves to returning names that are links to advertisements rather than the sites the original user requested Network Tools You won t use them often if your LAN and your Internet connection are working properly but you should know about a handful of troubleshooting tools that allow you to examine the innards of your network and its Internet connection All of these tools are simple text commands that you can use with just about any operating system When you type a command the system will display the results in the same window or screen In Microsoft Windows you can open a Command Prompt window after selecting Start Programs or by selecting Start Run and then typing
327. rvice to provide the links Figure 3 5 shows a simple LAN connected to a WAN Your Internet service provider JSP uses a WAN to connect you to the Internet The Internet itself is a set of connection points that link a lot of WANs It s also possible to connect a single computer directly toa WAN without going through a LAN If you have just one computer and it s connected directly to a modem your computer is on your ISP s WAN Hubs Switches and Routers 31 32 Desktop computer Desktop computer Router 7 computer Figure 3 5 A LAN is usually limited to a single building or some other small space a WAN can connect several LANs Bridges and Routers NOTE Chapter 3 Any time you connect two networks you must use a tool that translates the address and control data used by each network into values that the other network can understand When the device simply examines the address on each packet and decides which packets to forward to the other network it s a bridge When the device examines the address or routing information in each packet and sends the packet along to its ultimate destination which might be in yet another LAN far from the original it s a router Bridges and routers operate between two different networks Don t confuse them with switches and hubs that distribute data within a network However many routers combine functions with a switch in a single device When you connect your LA
328. s Origin Hey destination I have some data for you Destination Okay origin go ahead I m ready Origin Here comes the data Origin Data data data data checksum Origin That s the message Did you get it Types of Network Connections 13 14 Ethernet Chapter 2 Destination I got something but it appears to be damaged Origin Here it is again Origin Data data data data checksum Origin Did you get it that time Destination Yup I got it I m ready for more data We can leave the specific form of handshaking information to the network designers and engineers but it s important to understand that not every bit that moves through a computer data network is part of the original block of information that arrived at the input computer In a complex net work such as a wireless data channel as much as 40 percent or more of the transmitted data is handshaking and other overhead It s all essential but every one of those bits increases the amount of time that the message needs to move through the network Ethernet was introduced in the 1970s as a method for connecting multiple computers and related equipment in the same building Ethernet offers several advantages It s fast it s extremely flexible it s relatively easy to install and use and it s inexpensive It has become an industry standard supported by dozens of manufacturers so you can use different b
329. s but you still have to know which black boxes to use And when something goes wrong knowing what s inside those boxes will make troubleshooting a lot easier Before we talk about specific network types let s look at the common elements of every computer network As you probably know computers reduce all information to only two information states Either a signal is present or there is no signal These two conditions are usually described as 1 and 0 or on and off or mark and space Each instance of a 1 or a 0 is a bit Anything described as digital can be reduced to those ones and zeroes The form that each or 0 takes is different in different types of com munication channels It could be a light sound or electrical charge that is either on or off a series of long and short sounds or light flashes or two different audio tones electrical voltages or radio frequencies In a very simple system the 1 might correspond to yes and the 0 to no or any other pair of options Individual bits only offer two options so they re not particularly useful but when you string eight of them together into a byte you can have 256 different combinations 2 x 2x 2 x 2 x 2 x 2 x 2 x 2 That s enough to assign a different sequence to every letter of the alphabet both upper and lowercase the ten digits from 0 to 9 spaces between words and other symbols such as punctuation marks and many letters used in foreign alphabe
330. s and file transfers from trusted users to the Internet Therefore a legitimate user can connect to network nodes on the wired part of a mixed LAN or on the Internet but an intruder would be cut off at the firewall Because authorized wireless users and intruders are both on the unprotected side of the firewall it does not isolate the wireless nodes from one another An intruder can still gain access to another computer on the same wireless network and read shared files so it s a good idea to turn off file sharing on any computer connected to a wireless network and to use firewall software on individual computers A firewall for a wireless network should use some kind of authentication to allow legitimate users through the gateway but it should reject everybody else If access control based on MAC addresses is built into Wi Fi networks and the added authentication in 802 1x are not adequate then an outboard firewall should require all users to enter a login and password before they can connect to the Internet If your wireless network includes computers running more than one operating system your firewall must use a login tool that works on any plat form The easiest way to accomplish this is with a web based authentication server such as the one included with the Apache web server http httpd apache org The Apache web server is available as a Linux or Unix application that can run on an old slow computer with an early Pentium or
331. s such as Windows Home Server and its associated client programs include software that has been optimized for video distribution but you can also use a general purpose Linux Unix Macintosh or Windows server as long as the server computer contains one or more relatively large hard drives with enough available space to hold very large video files Other media servers combine the function of a network server and a local media player into a single package You can play music and videos through a screen and speakers connected directly to the media server or send requests to the server from other players through your network Other Things You Can Connect to Your Network 215 216 Chapter 15 TiVo and Other Digital Video Recorders The primary function of a digital video recorder DVR is to record incoming broadcast or cable television programs for delayed viewing However some DVRs including TiVo the most popular DVR in North America and Australia can also distribute programs to another DVR through a network By connect ing a TiVo to a network you can also download program schedules through the Internet rather than a slower dial up telephone connection Most recent TiVo models including the Series2 Dual Tuner and Series3 HD DVRs have an Ethernet port as standard equipment The older Series2 Single Tuner DVR requires an optional Ethernet network adapter that connects to the DVR s USB port For a wireless connection you must use a Ti
332. s XP Home Edition the Backup utility doesn t automatically load when you install the operating system Apparently somebody at Microsoft thought that Home Edition users didn t need to back up their data Go figure To install Windows Backup from the XP Home Edition CD follow these steps Place the XP CD in your computer s drive When the Welcome message appears select Perform additional tasks Select the Browse this CD option Open the ValueAdd folder and then the Msft folder and finally the Nibackup folder 5 Run the Ntbackup msi program This will start a wizard that installs the Backup program Pepe hor x Installing Backup in Windows Vista Most versions of Windows Vista except Vista Starter and Home Basic include an automatic utility that can store backup files on a network server but it doesn t run until you turn it on To configure the Vista Backup utility select Start gt All Programs or Programs in the Classic start menu Accessories gt System Tools gt Backup Status and Configuration The Backup Status and Configuration tool shown in Figure 9 8 will appear on Backup Status and Configuration te ga Automatic file backup is not set up A Cc When you set up automatic file backups Windows will make a copy of the files on your computer to a location of your choice System and program files will be Back Up Files skipped What file ty ed in the backup P a Afterwards Windows will
333. s a printer to a network using a parallel port or a USB port When you shop for a printer server look for one that uses the same type of printer port as your printer Most modern printers have USB ports but older units with parallel ports are still common If your printer has both USB and parallel ports use the USB port External printer servers are a good choice when your network includes computers in more than one room and you have at least one spare port on the network hub or router You can run an Ethernet cable to the server unit NOTE directly from the hub in the same room or from an unused wall outlet in another room If you don t have enough Ethernet ports in the room where you want to place the printer server connect the computer and the printer server to the network through an inexpensive Ethernet data switch as shown in Figure 14 2 Desktop computer Desktop computer Desktop computer Router Figure 14 2 If you don t have a spare network outlet for a printer server use a small Ethernet data switch When you install Ethernet cables for your home or small business network consider the locations where you might want to install a printer Run an extra Ethernet cable between that room and your network hub and use a wall outlet plate or surface mount box with two or more RJ 45 jacks Use a different color jack for each outlet to make it easier to identify them at a glance Adding a printer server t
334. s computer IBF Local Private network Customize Access Local and Internet Connection Local Area Connection View status Sharing and Discovery Network discovery 9 00 x File sharing On v Public folder sharing On x Printer sharing off Y Password protected sharing ott Y See also Internet Options Media sharing On Y Windows Firewall Show me all the files and folders I am sharing Figure 13 10 Use the Set up a connection or network option to create a VPN link Select the Connect to a workplace option and click the Next button The wizard will ask if you want to use an existing connection Select the No create a new connection option The wizard will ask if you want to use a VPN or a dial up connection Select the Internet connection VPN option The wizard will then ask for details in the screen shown in Figure 13 11 Type the VPN server s address provided by the network manager in the Internet address field This can be either a numeric address or a name Type the name you want to use on your own computer for this VPN con nection in the Destination name field If you want to test the connection click the Next button If you don t want to connect select the Don t connect now option and then click Next The wizard will ask for your name and password Type the name and password you use for this VPN account If you want your computer to automatically send your password turn on the Remem ber this password op
335. s content MP3 files are entirely adequate for casual listening especially for speech but uncompressed files can sound a lot better The compromise between file size and sound quality is particularly important when you are loading files on an iPod or other portable device with a limited amount of storage space For a home system where you have little or no practical limit to the amount of storage space you can almost always add another hard drive to the server storing your music files in an uncompressed format especially if you plan to listen through a good quality stereo or surround sound system is best It s important to store archival copies of original recordings as uncompressed files so future users will have the best possible recordings to work with Many libraries and archives keep a high quality WAV file as a master copy and a separate MP3 listening copy for distribution Archiving uncompressed files is less important when you re deal ing with commercially available CDs because hundreds or thousands if not millions of other copies are probably in circulation but when you have the only copy archiving an uncompressed version can make a difference Many audio player programs can automatically recognize and load most common file formats However you might want to install more than one program just in case your default player can t handle a file For example Windows Media Player won t accept very high bit rate 24 bit
336. s over very long distances the antenna supplied with your adapter should be all you need Remember that a more powerful antenna might produce stronger incoming and outgoing signals but those stronger signals often don t make any dif ference to network performance once the signal strength reaches an adequate level there s no advantage to adding more power or sensitivity The antenna used with an access point is a different story If you install a high gain directional antenna or place the antenna as high as possible the access point s coverage area will increase because radio signals at the fre quencies that Wi Fi uses are line of sight meaning that the signal can reach anywhere that an observer at the same location could see However the off axis signals to or from a directional antenna are a great deal weaker because the antenna focuses most of its output from a transmitter or sensitivity toa receiver within a limited area When you install a directional antenna take the time to make sure the antenna is oriented for the best possible signal strength between the access point and the network interfaces On the other hand nondirectional or omnidirectional antennas have equal signal strength or sensitivity in all directions The best way to provide Wi Fi coverage over a wide area is to use an access point with a nondirectional antenna and either increase the height of the access point or antenna or use directional antennas
337. s specific requirements VPN Clients for Linux Unix Using a VPN client on a computer running Unix is more complicated than running a VPN from a Windows machine because the client is not integrated into the kernel Therefore you must find a client program that works with the version of Unix and the VPN protocol you re trying to use No single program offers a universal VPN client and some combinations such as PPTP on BSD Unix versions don t seem to exist at all Linux users however can choose from several IPsec implementations FreeS WAN _hiip www freeswan org pipsec hitp perso enst fr beyssac pipsec NIST Cerberus itp w3 antd nist gov tools cerberus IPsec is included in the OpenBSD distribution You can find a tutorial that explains how to use it at hitp tutorials papamike ca pub obsd_tpsec himl The IPsec implementation for FreeBSD is at Attp wwuw r4k net ipsec For information about NetBSD IPsec take a look at hitp www netbsd org Documentation network ipsec OpenVPN A Cross Platform Alternative OpenVPN hiip openupn net is an open source VPN that does not use IPSec It can operate on Windows Mac OS X Linux and Unix It s designed for ease of use and security even through noisy or otherwise unreliable networks Using a VPN Through a Public Network When you connect your laptop to your corporate LAN through a public network at an airport or in a conference center or if you re using a broad band
338. s to conduct a conversation on a display screen and audio or video messaging where a microphone and or a camera replace or supplement the keyboard Live messaging is more immediate than email because it arrives on the recipient s screen as soon as the originator hits the Send button rather than waiting for a mail server to forward each message Assuming the distant com puter is turned on and the messaging program is running the text appears on the screen or the sender s voice comes through the computer s speakers immediately Live messaging makes it possible to conduct a text based conversation through the network without the time delay that comes with sending and receiving email The most common uses for instant messages involve brief questions and answers such as requests for specific items of information Hey Sarah I m on the telephone with a customer How many Size 4 gizmo brackets do we have in stock invitations to face to face meetings Can you meet me in ten minutes in my office or Do you have plans for lunch and purely social exchanges among friends and family IM has also become the medium of choice for online gossip among teens and preteens IM has a specific place in the hierarchy of communication methods It s less formal and more immediate than email or facsimile fax less intrusive than telephone calls and more civilized than shouting from one room to another In some businesses and families IM is an essent
339. sant programs called rootkits that take control of a PC or display threatening messages An unprotected system with a lot of unused storage space can be an attractive target for hackers who want to distribute pirated software music or video files you didn t think they store that stuff on their own computers did your The number of such idiots and creeps on the Internet is surprisingly large if you install a firewall that notifies you when an outside computer tries to connect to your network your firewall log will probably list several break in attempts every day Wireless Access Points with Firewalls The easiest firewall to use with a wireless network is one that s built into an access point Many wireless access points combine the functions of a wire less access point with a broadband router and an Ethernet switch so they support both wired and wireless network clients As you know a network router translates addresses between the numeric IP address that identifies the LAN to the Internet and the internal IP addresses that identify individual computers within the local network The firewall normally blocks all incoming requests for data to network hosts but this creates problems when you want to use one or more of the computers on the local network as file servers So the firewall redirects certain types of requests to the appropriate computer inside the firewall Each request to connect to a server includes a specific port numbe
340. scan your system on a schedule that you spedfy New C3 or updated files will be automatically added to your backup Restore Files Enabling automatic file backup will help protect your files from loss or accidental deletion Set up automatic file backup Choose your backup settings and run your first backup Change backup settings Figure 9 8 Use the Backup Status and Configuration tool to set up an automatic file backup The Backup Status and Configuration tool will step through a series of windows that request the specific information needed to run automatic backups Macintosh Backup Programs The same general principles apply to creating and restoring backups on a Mac Make backups on a regular schedule and store the backup files on a file server removable media or both The Time Machine program included in OS X can automatically create backups to an external drive or a networked drive as shown in Figure 9 9 Several alternative Mac backup programs can also send backup files to a network including SuperDuper Aitp www shirt pocket com SuperDuper SuperDuperDescription html Synk Backup http www decimus net comparison php iBackup Attp wwuw grapefruit ch iBackup Mac Backup Attp wiww mac com 1 solutions backup html File Servers 103 104 Chapter 9 eo Time Machine D Name SATA External Hard Disk Available 7 7 GB of 74 2 GB Oldest Backup Change Disk Latest Backup
341. se a similar program to speak to the person at the distant computer rather than using the keyboard and screen And if you add a camera at each end you can use a video messaging system that allows each of you to see the other party during the conversation Within a home or small office network you can use instant messaging with or without sound and pictures to communicate from one room to another It might be a simple message such as Dinner s ready or a more complicated request for information from someone else in the building And of course if there are young people in the house the instant message program will quickly become a channel for gossip and idle conversation For more about instant messaging programs see Chapter 16 Sharing Printers and Other Hardware In most homes and small businesses there s no need for every computer to have a printer available for its exclusive use because nobody uses a printer all the time It s often more practical to attach a single printer to a network or maybe one for black and white pages and another for color rather than buying a separate printer for each computer When you only need a single printer you can often buy one that provides better images and faster performance for considerably less than the price of two or three cheaper models The same kind of economy can also apply to a flatbed scanner and other specialized input or output devices A network printer can either connect dire
342. se e Game Consoles tise E Connecting PlayStati ri cerei rette dele gg roe nee Trente e eg Connecting a WI epi tt ERE OUO PA DRE Connecting an Xbox 360 15 in eiie deer tte eee be Re teg etn Connecting Home Appliances to Your Network sss Home Avlomation visio c2 re iere cte te terit tet Ot deep heir He ERO ATAN Remote Sensors and Controls sss eee Bar Code Readers and Remote Data Entry ssssssse If You Can Convert It to Digits You Can Put It on the Network 16 OTHER NETWORK APPLICATIONS Remote Desktop zc D D EE UP E EE eesti Windows Remote Desktop sss Virtual Network Computing VNC sss MaxiVista Adding a Sreem enpiri estier there lieto esten er Terhes Multiple Monitors 1 i estre bees etae bead een ee dee ene dn Remote Control tee pee ete bee e ce ied e Erie ege Synchronizing Files ss rr eee eee ee IH EET SR Ree e edd Contents in Detail xi Instant Messaging and Live Communication ccccceseeceeeeseeeeeeneeeneestseseeeeneesneeeaas 233 Servers vs Peer to Peer Messaging sess 234 Internet Based IM Services sss eme 234 Messaging Through a LAN sere iere tret t e eee eire 235 Messaging Through a Virtual Private Network sse 236 Audio and Video Messaging eee 237 17 TROUBLESHOOTING 239 General Troubleshooting Techniques sss 240 Define the Problem sssssssssssseeeeeeeen
343. sensitivity to lightning strikes Remember to use appropriate lightning suppression wherever practical Bar Code Readers and Remote Data Entry One more possible use of a small business network could be remote entry of information to a central computer This might include a portable bar code reader used for inventory control or property management security devices for controlled access and networked cash registers and other point of sale devices If You Can Convert It to Digits You Can Put It on the Network Chapter 15 The most familiar uses of a data network are the ones that involve a computer or a game console but the same network can also handle other forms of digital data Today s technology makes it possible to convert almost any kind of information to digital form if you can t find off the shelf equipment and software that can do the job you have in mind you can probably assemble a system from standard parts and software As you install your home network think about it as a household utility just like electricity telephone service and water Even if you only use your network to connect computers to the Internet today it s entirely possible that new and unexpected uses will appear in the future OTHER NETWORK APPLICATIONS number of purposes they share files and messages connect to the Internet and maybe play multiplayer games or listen to music and watch videos from a server But once you have your home
344. sensor or operated with a relay Most of these applications are more practical for relatively large businesses and government agencies that operate in several locations such as a county or statewide system of radio transmitters or a scientific study that allows researchers in multiple locations to track environmental conditions through the Web but some can be adapted for a home or small business network For example a water detector in the cellar might trigger an alarm or send an email message or an intrusion alarm a fire alarm and a remote temperature sensor in a barn could all connect to a network on a farm through a Wi Fi link to a computer or other monitoring device in the house Or with the right kind of equipment connected to your home network you could send an instruction through the Internet from your workplace in case of a sudden snowstorm that would turn on heating coils embedded in your driveway and melt the ice before you arrive home For that matter you could even operate a model railroad through your network but you ll need somebody near the tracks to take care of derailments and other scale model disasters Remote controls thermostats sensors and monitors are specialized devices but they re widely available through industrial sources and from retailers and mail web order suppliers of home automation equipment Every remote sensor and control that connects to your network through a wire or cable increases the network s
345. sharing SMB so that s the best way to exchange files between an up to date Mac and another computer through a network I ll discuss connecting older Macs to a network later in this section If your home or business uses Macintosh computers exclusively you could use one of the older Apple sharing services but you re on your own for that we re concerned here about connecting your Mac to a non proprietary network Connecting a Mac to a Windows SMB Network When a Macintosh is connected to an SMB Windows network it appears the same as any other computer connected to the network You can find drives directories files and other resources connected to the Mac directly from your Windows or Linux Unix desktop In most cases connecting a Mac to a Windows network is a plug and play process Simply plug an Ethernet cable into the socket or turn on your Wi Fi adapter and the computer will automatically detect the network However your computer won t accept connections from the network unless the user logged in on the other computer also has an account on your Mac Unlike Windows Mac OS X won t accept connections from a guest account Sharing Files Through Your Network 143 144 Chapter 12 Adding a New Account To establish a new account in Mac OS X follow these steps From the Apple menu select System Preferences 2 Select View gt Accounts 3 In OS X 10 2 select New User in later versions click the button The
346. so all of the packets that move through the wireless portion of the network are encoded For clarity the diagram shows the VPN server as a separate component but the most practical way to add VPN security to a wireless LAN is to use a router or gateway that incorporates VPN support VPN enabled routers are available from several vendors including Cisco NETGEAR and TRENDnet go Access point Figure 13 4 A VPN provides a secure connection between a wireless network and an Internet gateway or a local LAN VPN Methods A VPN moves data through one or more intermediate networks to a desti nation on another network The VPN s tunneling client encapsulates the existing data packets or frames by adding a new header with the routing information that instructs the packets how to reach the VPN s endpoint The transmission path through the intermediate networks is called a tunnel Atthe other end of the tunnel the VPN server removes the tunneling header and forwards the data to the destination specified by the next layer of headers The exact form of the tunnel doesn t make any difference to the data because the data treats the tunnel as a point to point connection Network Security 161 162 Chapter 13 The tunneling headers can take several forms The methods used most widely in VPNs are Point to Point Tunneling Protocol PPTP Layer Two Tunneling Protocol L2TP and IP Security IPsec mode PPTP and L2TP can move data through IP IPX
347. so be a central storage location for photographs music and video files and allow users to view or play them through any computer in the house or through a television stereo or home entertainment system Chapter 15 explains how to use a network as part of a home entertainment system Choosing a Computer to Use as a File Server You can use just about any computer as a file server If you have a spare computer or an older unit that no longer has enough computing power for day to day use that might be a good candidate especially if you just want to share files and add network storage capacity You will probably get better performance from an older computer if you add some extra memory and one or more new hard drives Linux server software only needs about 10GB of hard drive space but an older hard drive could be more likely to fail due to age and wear And of course you will also need disk space for all the files that you store on the server If you want to use the server for more than just storage and file sharing you can buy or build a new purpose built server with space for several storage drives and special server software that includes additional features and functions such as web hosting and automatic backups All of the major office computer manufacturers including IBM Dell Compaq and Apple sell server computers with software already installed Windows Mac Linux or Chapter 9 Every computer needs an operating system
348. splay the SSIDs of every nearby wireless network Normally most Wi Fi access points send out beacon signals that broadcast the network s SSID When a network adapter performs a radio scan it detects those beacon signals and displays a list of nearby SSIDs in its control program However you can disable the SSID broadcast so the network doesn t show up on most control program scans To connect a computer to a network whose name is not visible you must instruct your control program to search for the SSID A nonbroadcast SSID is not completely invisible A sniffer program such as Network Stumbler can still detect it and display the SSID and every time a user connects to the network the network adapter sends the SSID in a packet that can be easily sniffed Disabling the SSID broadcast might in some cases make it easier for an attacker to later attack the laptop of one of your users this is a more serious issue for businesses or corporate network administrators than for people running home networks Because the laptop cannot know if the hidden network is available it must constantly probe for the network announcing its presence and giving an attacker much of the information needed to spoof the hidden network Because a hidden network must be in a laptop s Preferred Networks list the laptop will automatically connect to the spoofed network WEP Encryption WEP encryption is an option in every Wi Fi system so it s important to k
349. ss extravagant If you ve already wired your house or apartment for a data network you can add an entertainment server and connect stereos or TVs in several rooms without spending a small fortune You can also connect entertainment devices to your network in stages rather than spend a lot of money at one time A tremendous variety of equipment and services is available that can fit within the home entertainment systems category but for this book s purposes I ll consider the processes of distributing music video and games through a home network and playing them on TVs stereo systems surround sound systems and table radios Music Through a Home Network Chapter 15 Any technology that reproduces sound has at least two elements a source and a destination Often one or more additional intermediate elements are between the source and destination such as a preamplifier that boosts volume level or an analog to digital or digital to analog converter but you ll always have a program source and a destination device that converts the signal back to sound For example consider an antique gramophone like the one shown in Figure 15 2 The source of the sound is a needle that follows the vibrations in a grooved disk and the destination is a membrane that reproduces those vibrations through a horn In a modern music system the program source can include the following e Analog media such as vinyl disks or magnetic tape e Digital media suc
350. ssible but they re almost always provided as supplements to other services These systems use the internal telephone wiring that connects extension telephones in several rooms or the coaxial cable coax that provides cable TV signals The industry group that promotes home networks through telephone wires is called HomePNA the Home Phoneline Networking Alliance MoCA Multimedia over Coax Alliance is the comparable group for coax Types of Network Connections 17 18 Don t confuse internal telephone or coax wiring with the DSL and cable services that connect high speed Internet service to your home or business LAN HomePNA and MoCA are strictly for distributing network service within a building HomePNA and MoCA are less flexible than HomePlug network wiring because most homes already have a lot more built in AC power sockets than telephone or TV outlets However if the phone boxes or cable outlets are already in convenient locations it might be practical to consider HomePNA or MoCA as an alternative to Wi Fi or separate Ethernet wiring DTE and DCE Equipment Chapter 2 There s one more concept that every network planner should understand the difference between data terminal equipment DTE and data communications equipment or data circuit terminating equipment DCE If you re clear on these two types of network devices you will avoid a lot of headaches caused by communication failures Data can move through a wire in only on
351. sys tem The console will tell you that it s initiating a test Click OK The Wii console will test your connection If it s successful you re ready to use your game console on the network If it fails try one of these fixes e Check your firewall settings e Ifthe console displays an error code go to http www nintendo com consumer systems wii en en ma errors index jsp to find an explanation for the code Other Things You Can Connect to Your Network 221 222 Connecting an Xbox 360 If you use your Microsoft Xbox 360 game console and a computer in the same room but you have only one network jack or outlet in that room you can run the network connection to the computer through the game console Follow these steps to connect a Microsoft Xbox 360 console to your network 1 Turn off or disconnect power to your computer your network s router hub modem and the Xbox 360 console 2 Ifyou don t have a second network outlet in the room disconnect the Ethernet cable from the computer and plug it into the Xbox 360 con sole The cable should now run from the game console to the network hub or router 3 Ifyou have access to a spare outlet you don t have to disconnect the computer Just run a new cable from the game console to the free net work outlet or directly to an open port on the hub or router 4 Ifnecessary plug one end of a second Ethernet cable into the Xbox 360 console and the other end into your computer
352. t ert Re eig 150 Using Shares eoe testis acu teer me dois Coates a E oan tte oct te tid ERU DU N 150 13 NETWORK SECURITY 151 Keeping Intr ders OUF i i ctetu tere epit a deci bee ope ee ioc tt tete sre debe 152 User Accounts and Access Levels sss 152 Passwords de trae Mr AULEM Mee TAE DUE ADD HUE SM de A rs 152 Firewalls 25 ca ite Sandor ce scit trate toti quae iuipu eei et eed tpe ie dee bes 154 Virtual Private Networks sce cee neces n ret rome teet e eer ER eat erae e eed eee PR Re 159 VPN pu uapn M EET 161 MPINESerVers oo deep teretes pepe e erre cert ee ems 162 VPN Client Software te torre teneret seen eels re er Der eoi dete xen eee 165 VPN Clients for Linux Unix eeee eene re nenne nee 172 OpenVPN A Cross Platform Alternative sss 173 Using a VPN Through a Public Network 173 Wireless Securlly inore rak eise emere teet e eb ert beer esee pee dune ed O ins 174 Protecting Your Network and Your Data sssee 176 Network Nome 4 eei ene t tu etm RR eere testi ete eda 177 WEP EnC PHON Em 179 ADAAL ET oe teer terr I A TTA T 182 Access Control MAC Authentication cccccccccceeeeceenseeeseeeesteeeeneeesneees 184 Physical Security 024 Saath te ete ed toe dle cbs tales Be bet epe o eegpee hoes des 184 Windows Update and Patches ssssssssseee eee eee een 185 Microsoft Baseline Security Analyzer eee 188 Controlling Your Own Users sse eme em emen 189
353. t window like the one in Figure 13 12 will appear Connect VPN to Internet 2 x Username Password Save this user name and password for the following users s We only Anyone who uses this computer Cancel Properties Help Figure 13 12 Use the Connect VPN to Internet window to configure a VPN in Windows XP Click the Properties button The Properties window for your VPN client will appear Figure 13 13 shows the General tab of the VPN to Internet Properties window VPN to Internet Properties Options Security Networking Advanced lexample co Figure 13 13 The General tab controls the destination of a VPN connection 4 TheIP address of the VPN server should already be visible in the Host name or IP address of destination field The Dial another connection first option should be disabled Click the Networking tab to view the dia log shown in Figure 13 14 dud to Internet Properties Figure 13 14 The Networking tab controls the VPN s network configuration options Network Security 171 172 Chapter 13 5 Select the type of VPN server your network will use from the Type of VPN menu If you don t know the VPN type select the Automatic option 6 Select Internet Protocol TCP IP or Internet Protocol Version 4 from the list of connection items and click the Properties button to change the network settings including
354. te computers Installing an all in one is like installing a printer Connect the USB connector to the computer you want to use as a printer server or connect the Ethernet port directly to the network hub or router If the server doesn t automatically detect the all in one device load the software supplied with the device If all else fails follow the installation instructions supplied with the all in one device Printers and Other Devices on Your Network 201 OTHER THINGS YOU CAN CONNECT TO YOUR NETWORK AUDIO VIDEO HOME ENTERTAINMENT AND BEYOND data you can transmit that data through a network and either convert it back to its original form or use it as input data for a com puter With the right kind of input and output devices you can use the same network that shares computer resources to monitor and control industrial processes listen to sound from a microphone or watch images from a camera distribute audio and video through your home or business and operate equipment by remote control And if the network is connected to the Internet you can do all those things to or from anywhere with an Internet connection Many of these network applications are extremely specialized such as monitoring the temperature of the water in a stream but others are often practical for a home or small business network For example you can use your network to watch or listen to activity in another room or to distribute audio and video fi
355. ted to the network must be within the ranges defined by the router or modem The next section explains how each of these LAN side settings works Individual Computers Each computer connected to a LAN must have the same configuration set tings in relation to the router that the router has with the WAN a numeric IP address a network mask and addresses for a gateway to the Internet and one or more DNS servers As the person responsible for your network you must set up a DHCP server and either provide these values to each of your users and make sure they enter them correctly or type them into each com puter and network device yourself The differences between setting up a router to talk to the Internet and setting up a computer to talk to the local area network are 1 the router has two groups of settings the WAN and the LAN but the computer has only one and 2 the router obtains its WAN settings from your Internet service provider but the local computer gets many of the same settings from the router Therefore you should almost always set up the gateway router in your network first before you add computers to the network When you connect a single computer directly to the Internet through a high speed DSL or cable modem you must use the settings supplied by your ISP or the modem The essential settings for connecting a computer to the Internet through a LAN are similar to the ones that you use to set up the modem and the router
356. ted computer running Linux or one of the BSD versions of Unix can be an inexpensive VPN server Or if you re using a Windows server for other purposes a dedicated computer can also provide VPN support at little or no additional cost But a full size network server is often a bigger and more complicated solution to a relatively simple problem They re not always the best choice Many switches routers gateways and firewall devices also include VPN support Cisco 3COM Intel and many other manufacturers make VPN products that are often easier to install and maintain than a separate computer In a wireless network the VPN server does not need all the same bells and whistles as a server in a larger corporate network As Figure 13 5 shows a router located between the wireless access point and the wired portion of an enterprise network can easily double as a VPN server In a home network the VPN server can operate between the access point and a DSL or cable modem server a point Ethernet Figure 13 5 A network router can also act as a VPN server for a wireless network Stand alone VPN client hardware that sits between the computer and the network is also available but this setup isn t as practical in a wireless network because the wireless network adapter is almost always plugged directly into the computer itself VPN Client Software A wireless client connects to a VPN server through its wireless Ethernet link to the netwo
357. ter For example your ISP might use a WAN with the network address 203 23 145 XXX the individual computers and LANs connected to that WAN would have addresses from 203 23 145 000 to 203 23 145 255 In this case the subnet mask would be 255 255 255 0 because the local address is limited to the last part of the address the zero A maximum of 256 devices numbered 0 through 255 can be connected to this subnet Within your own LAN you can use subnet masking to divide the network into two or more subnets Dividing the network into subnets is useful when you want to separate your wired connections from the Wi Fi access point or when you want to use an internal firewall to isolate computers that contain sensitive personnel or financial data from the rest of the network To divide your LAN into two equal size subnets assign the subnet mask XXX XXX XXX 0 to one subnet and use local addresses from 1 to 126 use 0 for the router For the other subnet use the subnet mask XXX XXX XXX 128 and assign addresses between 129 and 255 You will need a separate router for each subnet Using subnets to split a LAN into separate groups counts as an advanced networking practice youre not likely to see this setup in a simple home or very small business network Connecting Your Network to the Internet 113 114 NOTE Chapter 10 IP Addresses As Chapter 4 explained several groups of numeric IP addresses have been reserved for computers and other devi
358. ter and monitor so a small UPS should be enough to keep your network alive for up to an hour Of course during a power failure you will be able to use the network only with laptops and other battery powered portables The battery in a UPS is relatively heavy so you will probably want to place the UPS on the floor rather than on a shelf on the control panel If the UPS does not have enough battery backup outlets for all of the equipment in your control center plug a power strip directly into an outlet on the UPS Installing the Network Control Center and Ethernet Cables l 62 Chapter 6 Modems Routers and Switches If you already have broadband Internet service take a close look at the modem that connects your computer to the telephone line or TV cable and the instruction sheet that was provided with the modem Some Internet service providers supply modems such as the one shown in Figure 6 5 that double as gateway routers switches and or Wi Fi access points If you have a combined unit there s no need to duplicate those functions with one or more separate boxes REN I Photo courtesy of 2Wire Inc Figure 6 5 This DSL modem includes a four port switch and a Wi Fi base station Your floor plan should contain enough information to tell you the number of nodes in your network You will need one port on a switch or combined switch router for each node plus additional ports to connect the control devices For example i
359. ter than a computer for less money If you re buying new equipment to play music through your network a dedicated music player can Other Things You Can Connect to Your Network 213 214 Chapter 15 be an excellent choice but if you already have a spare computer you can probably accomplish the same thing without buying any new equipment although replacing the computer s audio interface might improve the system s performance Headphone Analog Digital Digital Ethernet Power mini jack audio optical coax RCA output output Photo courtesy of Slim Devices Figure 15 5 Slim Devices Squeezebox connects a music server to a home audio system through an Ethernet or Wi Fi network Networked Receivers and Internet Radios It s not necessary to use a computer or a full scale stereo or surround sound system just to listen to music from a music server or streaming radio stations and music channels through the Internet You can find a whole category of tabletop Internet radios that combine the music client and speaker in a single box sometimes with satellite speakers for stereo In spite of the name most Internet radios can also play music files stored on your own music server Some also include AM and FM radios so you can use the same device to listen to local broadcast stations An Internet radio works like any other network music client It connects to your home network through an Internet port or a builtin Wi Fi port and allo
360. th an Internet connection If any Internet technique can eliminate the apparent distance between you and your LAN your office and your colleagues without sacrificing security a virtual private network is that technique Wireless Security Chapter 13 Wireless networks are not secure They are safe enough for many users most of the time but it s just not possible to make a network that uses radio to exchange data absolutely private Wireless networks are a trade off between security and convenience The obvious benefits of a wireless network connection fast and easy access to the network from a portable computer or an isolated location come at a cost For most users the convenience of wireless operation outweighs the possible security threats But just as you lock the doors of your car when you park it on the street you should take similar steps to protect your network and your data The simple truth is that a wireless network uses radio signals with a well defined set of characteristics so somebody who wants to dedicate enough time and effort to monitoring those signals can probably find a way to intercept and read the data contained in them If you send confidential information through a wireless link an eavesdropper can copy them Credit card numbers account passwords and other personal information are all vulnerable An entire catalog of tools for cracking Wi Fi encryption methods is easy to find on the Internet Although 3G
361. the circuit or in the case of carrier pigeons an attack by a marauding hawk Whatever the source noise in the channel can interrupt the flow of data In a modern communications system those bits are pouring through the circuit extremely quickly millions of them every second so a noise hit for even a fraction of a second can obliterate enough bits to turn your data into digital gibberish Therefore your data stream must include a process called error checking Error checking is accomplished by adding some kind of standard information to each byte In a simple computer data network the handshaking informa tion is called the parity bit which tells the device receiving each byte whether the sum of the ones and zeroes inside the byte is odd or even This value is called a checksum If the receiving device discovers that the parity bit is not correct it instructs the transmitter to send the same byte again More complex networks including wireless systems include additional error checking hand shaking data with each string of data Handshaking and Overhead The computer that originates a message or a stream of data can t just jump online and start sending bytes First it has to warn the device at the other end that it is ready to send and make sure the intended recipient is ready to accept data To accomplish this a series of handshaking requests and answers must surround the actual data The sequence of requests goes something like thi
362. this folder 6 Check the Make this folder private checkbox to limit access to the files in this folder Click again to remove the checkmark and allow other users to see this folder 7 Click OK to save your choice and close the Properties window Level 2 Files stored in Level 2 drives and folders are accessible to the owner of those drives and folders and to anybody with an administrator level account on the computer where the folders and files are stored Other users on this computer and all users on other computers connected to this computer through the network can t open these files To assign a drive or folder to Level 2 follow these steps 1 From My Computer right click the drive or folder icon you want to assign to Level 2 A pop up menu will appear next to the icon 2 Select Sharing and Security A Properties window will appear with the Sharing tab visible 3 Disable the Make this folder private option and the Share this folder on the network option If a checkmark appears in either box click the box to remove it 4 Click OK to save your choice and close the Properties window Level 3 The owner of Level 3 folders and files and any user with an administrator level account on the same computer can read change or delete Level 3 folders and files all others using the same computer can read or open these files but they can t change or delete them In Windows XP Power Users can also change and delete Level 3 fil
363. tion Click the Create button to establish the VPN connection and close the wizard e Connectto a workplace Type the Internet address to connect to Your network administrator can give you this address Internet address vpn myhomeoffice com VPN Connection Destination name Use a smart card e Allow other people to use this connection This option allows anyone with access to this computer to use this connection Don t connect now just set it up so I can connect later Next Cancel Figure 13 11 Use this screen to configure your VPN To create a shortcut to a VPN on your desktop in Windows follow these steps 1 In XP open the Control Panel and select Network Connections In Vista open the Control Panel select the Network and Sharing Center and select Manage Network Connections from the Tasks list 2 From the Network Connections window right click the icon or listing for the VPN and select Create Shortcut from the pop up menu 3 Apop up window will ask if you want to place the shortcut on the desk top Click the Yes button A shortcut will now appear on the desktop The Microsoft L2TP IPsec VPN Client Microsoft includes a client for L2TP connections with Internet Protocol security IPsec in Windows 2000 Windows XP and Windows Vista A similar client program for Windows 98 Windows Me and Windows NT Workstation 4 0 is available for free download from ttp download microsoft com downl
364. ts A byte is the basic building block of computer communication The most widely used coding system for converting bytes to characters is called ASCH American Standard Code for Information Interchange Figure 2 1 shows a typical sequence of two bytes Figure 2 1 These bits form the ASCII sequence of A 01000001 and n 01101110 ASCII is fine for text but a computer can also convert many other forms of information to digital data For example it can divide every second of sound from a microphone or an analog recording into thousands of very short segments and use 16 or 24 bits to specify the content of each segment or divide a picture into millions of individual points called pixels short for picture elements and use a series of bits to specify the color of each bit A wire or other data link can carry only one bit at a time Either there s a signal on the line or there isn t Over short distances it s possible to send the data through a cable that carries eight or some multiple of eight signals in parallel through eight separate wires Obviously a parallel connection can be eight times faster than sending one bit at a time through a single wire but those eight wires cost eight times as much as a single wire That added cost is insignificant when the wires extend only a foot or two but the additional cost www allitebooks com of parallel wires can add up quickly when you re trying to send the data over a long distance And
365. ture wireless networks with one or more central access points are called infrastructure networks Infrared Infrared connections use invisible flashing light it s invisible because it uses frequencies outside the range of human sight to exchange data between computers mobile telephones digital cameras and other devices Most of the wireless remote control units that you use with your television DVD player and home stereo system also use infrared light signals Infrared channels are often called IrDA connections because the Infrared Data Association IrDA has set the standards for infrared communication Many laptop computers have builtin IrDA ports usually in an incon spicuous location along the edge of the case The IrDA port is usually an infrared lens under a transparent plastic cover like the one shown in Figure 2 8 The camera captured the flashing infrared light even though it s not normally visible to the human eye www allitebooks com NOTE NOTE looks like a blank panel on the edge of the case As you have probably noticed with your TV s remote control infrared signals can bounce off walls and other objects so it s not absolutely necessary to point a pair of IrDA ports directly at each other especially when they re both indoors When two computers with active IrDA ports are in the same room they will usually detect each other automatically The infrared port on a laptop computer can detect an IrDA sig
366. tures But if your network s users print enough pages to justify a workgroup printer the added cost will often pay for better performance Automatic Printer Switches When two or more of your computers are located in the same room or adjacent rooms an automatic printer switch might be a less expensive alter native to a network printer server As the name suggests an automatic switch detects print requests from two or more input connectors and automatically forwards them to the printer and the switch returns status information from the printer back to the computer that originated the request When it receives more than one print request at the same time the printer switch sends the first one to the printer and holds the other requests in a buffer until the first one has completed printing As far as each computer attached to the switch is concerned the printer is connected directly to that computer A printer switch is less practical when the computers on your network are in rooms that are far apart because a cable must run from each computer to the switch Using a Computer as a Printer Server The alternative to a printer server for a network that extends beyond more than one or two rooms is to connect the printer directly to one of the network computers and send print requests from all the other computers through that one This approach has several advantages e You can use any printer connected to your computer e You don t n
367. two or more types of WPA encryption If your network includes a RADIUS server choose EAP If the network has no encryption server use the WPA TKIP option For a network user providing a WPA key is just as easy as providing a WEP key Most network adapters made in the last couple of years auto matically recognize the type of encryption embedded in each Wi Fi signal that they detect so the control program might ask for an encryption key without specifying whether it s a WEP key or a WPA key Attacking WPA Security It was probably inevitable that somebody would take the added security features in WPA encryption as a challenge and develop a WPA cracking tool Several such tools are out there so WPA does not provide the impene trable protection that some of its proponents might want you to believe In particular programs called coWPAtty and Aircrack ng both use dictionary attacks on WPA TKIP networks to try thousands or millions of possible keys until they find the correct one Fortunately neither of these programs nor any of the others aimed at cracking WPA encryption are easy to use and cracking a network can take a lot of time so successful attacks on WPA are not particularly common This technique takes time because the programs can only try about 50 different encryption keys per second but eventually they will find the right passphrase and connect to the target network Because each additional letter number or other character in a ke
368. ty programs but the settings are similar You can generally find the controls and settings by searching around each version s desktop Remember that some network control settings programs don t make permanent changes especially when you re loading the operating system from a CD or DVD or you re using versions of the ifconfig route command to assign IP netmask or other addresses To make a permanent change you must load the operating system on the computer s hard drive and edit the system configuration Checking the settings each time you start the computer is always good practice Summary No matter what kind of computer you re using the basic network configura tion settings are the same Either the computer obtains an IP address and related settings from the network s DHCP server or it uses settings from the network configuration utility The procedures in this chapter should give you enough information to set up a working network connection with any commonly used operating system Connecting Your Computer to a Network 129 SHARING FILES THROUGH YOUR NETWORK between convenience and security You want to make some of the files stored on your computer available to other people but you probably have other files that contain information you would prefer to keep private Therefore Windows and other network operating systems allow you to assign different files or directories to different access levels Some files are availab
369. ually work and how readers can develop and implement their own In this all new second edition author Jon Erickson uses practical examples to illustrate the fundamentals of serious hacking You ll learn about key con cepts underlying common exploits such as programming errors assembly language networking shellcode cryptography and more And the bundled Linux LiveCD provides an easy to use hands on learning environment This edition has been extensively updated and expanded including a new intro duction to the complex low level workings of computer FEBRUARY 2008 480 PP W CD 49 95 ISBN 978 1 59327 144 2 Se THE BOOK OF WIRELESS 2ND EDITION THE BOOK OF A Painless Guide to Wi Fi and Broadband Wireless WIRELESS by JOHN ROSS i x This plain English guide to popular wireless networking standards shows readers how to connect to wireless networks anywhere they go After an introduction to networking in general and wireless networking in particular the book explains all available standards including all flavors of wireless Ethernet Wi Fi along with new standards like WiMAX and 3G networks Readers will learn how to use wireless software to connect to the Internet wherever they are rather than waiting until they re in range of a public Wi Fi hot spot The Book of Wireless offers information about all of the cur rently available wireless services for Internet access with advice on how to understand the important differences b
370. udes laptops and other portables that connect and disconnect from the network DHCP is the better choice because it allows the network to assign an address automatically when a user connects and to re use the same address after the first user has disconnected Some Internet service providers and corporate network managers assign static IP addresses to each user whereas others use DHCP to generate addresses Chapters 10 and 11 explain how to set up your own computer and LAN to use either method The Domain Name System Computers have no trouble handling long strings of numbers but people often do Addresses in the form of words rather than numbers are generally easier to remember and use That s why the Internet and just about every LAN use names for each computer connected to a network In a LAN each computer reads the name of every other device on the same network auto matically on the Internet a computer called a Domain Name System server DNS server converts names to numeric addresses when you type the name of a website into a browser a DNS server finds the number that corresponds to that name and returns it to your browser which connects to that numeric address You or your network manager will assign a name to each computer when you set up your network your Internet service provider should set up a domain name for your connection to the Internet Within a LAN you can use simple descriptive names for each computer such as
371. uff Pushing Cable Through Walls NOTE This is a book about computer networks rather than home improvement or new home construction so it s not the place to describe all the special tools and techniques that electricians and telephone installers have been using for more than a hundred years to push wires through walls under moldings and inside closets If you plan to install your own internal wiring consult some of the do it yourself websites or look for a book about home wiring at your local home center before you start I can specifically recommend Wiring Home Networks Sunset Books 2004 as a guide to installing network wiring because I wrote it However several other illustrated books about home wiring also include the information you need Installing the Network Control Center and Ethernet Cables 57 58 NOTE In order to feed wires from wall plates or surface boxes through your walls to the control center you will have to drill some holes through base plates studs and other structural elements of your house or workplace If you re working in rooms on the ground floor you might be able to reach the spaces between the walls from below drilling upward from an unfinished ceiling in the basement or crawl space On the top floor you can work down ward from the attic But if you can t get to the inside of the walls from above or below your best option will be to cut holes in the wall and drill through the vertical studs or t
372. uivalent privacy WEP encryption 90 91 174 175 176 179 182 181 183 217 wired networks connecting to 216 220 wireless Ethernet See Wi Fi wireless fidelity gateway firewalls 158 network names 86 network standards 78 78 79 security 54 89 92 174 184 175 178 181 wireless fidelity See Wi Fi wireless fidelity Wireless Network Connection programs 87 87 89 88 122 Wireshark 248 249 250 wiring Ethernet 17 home run 51 52 52 53 installing 16 18 57 58 66 modular structured wiring center 59 63 telephone 17 18 wiring closets 31 50 Wiring Home Networks Ross 57 workgroup names 145 World Wide Web Consortium 24 WPA Wi Fi Protected Access encryption 54 78 90 91 136 160 174 176 179 181 182 183 194 217 WPA encryption 90 176 X Xbox 360 220 222 X Display Manager Control Protocol 226 XMBC Media Center 208 Y yahoo com 44 Yahoo Messenger 234 235 Z ZoneAlarm 158 Zune 24 The Electronic Frontier Foundation EFF is the leading organization defending civil liberties in the digital world We defend free speech on the Internet fight illegal surveillance promote the rights of innovators to develop new digital technologies and work to ensure that the rights and freedoms we enjoy are enhanced rather than eroded as our use of technology grows PRIVACY EFF has sued telecom giant AT amp T for giving the NSA unfettered access to the private communicati
373. ulate a different set of changes It s essential to maintain some kind control that synchronizes everything File synchronization software compares computer files across a network and incorporates all the additions moves changes and deletions from each copy into all the others When the file synchronizer finds a conflict between two versions it can flag the differences and allow a human editor or project manager to decide which version to accept Most file synchronizers compare and update the contents of folders or directories but they don t open and change individual files you must make an all or none decision about each file Some synchronizers are limited to Windows or Macintosh computers but others can compare files stored on computers that use different operating systems Here are some programs that are either available at no cost or as try before you buy downloads e Synchronize It hitp www grigsoft com winsin htm e GoodSync hitp www goodsync com e Microsoft SyncToy hitp www microsoft com downloads search for SyncToy e DirSync Pro hitp directorysync sourceforge net index himl e FreeFileSync http sourceforge net projects freefilesync Instant Messaging and Live Communication As the name suggests instant messaging IM is the process of sending text or other data that arrives at its destination almost immediately The most common forms are text messaging in which the participants use their key board
374. uld open any other kind of file The audio Other Things You Can Connect to Your Network 211 212 Chapter 15 output for the computer s audio interface should connect through an audio cable to a set of powered computer speakers or a full scale stereo or home theater system If you re using the computer exclusively as a music client you don t need the latest and most powerful processor or a large screen monitor Anything that can connect to the network and support a decent audio interface unit should be entirely adequate If you have an older laptop that you re no longer using for other purposes try using it as a music client the laptop is probably more compact than a desktop unit and it might work just as well if you plug a decent audio interface into the USB port Most computers look like well like computers If your stereo system is located on a bookshelf or behind glass cabinet doors in your living room you might prefer to use a music server that matches your other stereo components If you don t mind assembling a computer out of parts look for computer cases such as the Antec case shown in Figure 15 3 that look like stereo equipment But remember that you ll still need some kind of keyboard mouse and monitor On the other hand it s often easy enough to place the computer case out of sight on the floor or in some other out of the way location or to run the server through the network from another room Photo co
375. urtesy of Antec Figure 15 3 Some computer cases are designed to look like stereo components Connecting Your Network to Your Stereo If you don t have a spare computer you can also run audio cables between your stereo and a nearby computer that you re using for other purposes For example if you have both a desktop computer and a stereo system in your home office or study you can use that computer to feed the existing speakers through the stereo s amplifier Even if the stereo is in another room running audio cables through the wall or under the floor might be more practical Figure 15 4 shows a typical system connection To play music from your music server set the input selector on the stereo to the Auxiliary input or whichever input you have connected to the computer and use the computer s mouse and monitor to select the song or other music file you want to hear If your computer or sound card has digital outputs either optical or copper and the stereo has digital inputs use a digital cable to transfer the audio The computer should automatically open the music file in a compatible player and feed it to the stereo de Ethernet GP Music Wi Fi x server router Kg Digital or analog audio Music client CS Ethernet amp g Digital or analog audio Music Music server client Speaker Figure 15 4 A music server can connect to a client through either a Wi Fi link or an Ether net cable The cl
376. ut a 54 68 65 20 48 6f 75 73 The Hous e gave f 69 6e 61 6c 20 61 70 70 inal roval to 20 74 68 65 20 24 37 30 the 70 0 billio Figure 17 4 Wireshark uses contrasting colors to show different kinds of data frames 250 Chapter 17 ISP Problems As a formal or informal network manager you re often on your own when you re trying to find and fix a problem on your LAN but if you or one of your users discovers a problem using the Internet you might need help from your Internet service provider s ISP s support center and the people who run the computer or network at the other end of your connection Therefore you should find and keep the telephone numbers and email addresses of the ISP s help desk and the network tech center at the telephone company cable TV service or other company that provides the physical connection between your own LAN and your ISP The people who answer calls in those support centers are there to help you and they will often have tools that can test and monitor your network connection When you talk to a support representative ask for the case number or trouble ticket number that they have assigned to your problem if you have to call back later the case number will lead the person who takes your call to the notes about earlier calls Don t Panic Finally keep calm Your network does not have a mind of its own If you take a logical and organized approach to finding the cause of a network problem
377. ut to be too expensive and too intrusive to be practical for individual users As a business proposition call based picturephones were a complete flop But less expensive video devices and higher bandwidth have made it possible to send and receive both still pictures and full motion video through computer networks As a result many people have added online cameras webcams and microphones to their systems Both Microsoft s Windows Live Messenger shown in Figure 16 9 and Apple s iChat support video conversations in parallel with their text messag ing services They re both designed to operate through the Internet but there s nothing to stop you from using them to conduct conversations with other people on your LAN vi 0X D Karen ready for the weekend karentoh hotmail com BUGROSBS Rh 4 amp Thomas says Are we up for tonight guys Karen says I m down Thomas says oe So I ll see you later then J G 4 Z7 d 3 Tonight of course E Send Search ZA e E Play the new Windows Live Messenger Games Image courtesy of Microsoft Figure 16 9 Windows Live Messenger can add video images to simple text Other Network Applications 237 TROUBLESHOOTING When your network is working properly it s all but invisible you can send and receive files through the network between any pair of computers or other connected devices But when a connection fails or one of your users can t f
378. utton to open the Save As dialog Use either the Save In field or the finder window to navigate through the network to the folder on the file server where you want to store the backup file Choose that folder and click the Save button and then the Next button in the wizard window 6 The wizard will show you the details about the backup you are about to create If everything is correct click Finish The backup program will start To restore data from your backup files run the same Windows Backup program but select the Restore files and settings option in the Backup or Restore Wizard The reason you re making backups is to protect your data against loss or damage The most common problems that will destroy your original files are caused by either human error you really didn t mean to reformat that hard drive did you or damage to a disk drive When either of those events occur restoring the files from a network server is easy enough but if you lose your files because of a fire a power surge a lightning strike that damages the server along with the client computers or some other major disaster the backup files on the dead server won t do you much good Therefore creating at least one set of backup files on a set of DVDs tapes or removable hard drives and storing them in another location such as a friend s home or office or a safe deposit box at your bank is always good practice Installing Backup in XP Home Edition In Window
379. ven t already done so this is a good time to look around the rooms where you plan to install network outlets and the spaces directly above and below each room If you have access to an unfinished basement or attic you can run cables through the rafters and joists but if you have to run cables through finished walls and ceilings you will probably have to hide cables inside walls and behind baseboards and patch some holes after the wires are in place Either way look for the best routes for cables from each network outlet to the control center Use a pencil to mark the routes on your floor plan There are two ways to attach a network outlet to a wall For a finished appearance use a wall plate similar to the ones used for electrical outlets like the one shown in Figure 5 2 If the outlet will be hidden behind furniture or in some other place where it won t be visible you can use a small terminal block mounted on a baseboard like the one in Figure 5 4 Figure 5 4 A data terminal block can mount directly to a baseboard Trunks and Branches Using Secondary Switches There s an alternative to a pure home run wiring design for small networks that can make it possible to expand the network without having to run new cables all the way back to the control center This approach which vaguely resembles the trunks and branches of a tree or the tributaries of a river uses data switches to connect additional computers and other devices to th
380. vice Dial up network links are considerably slower than DSL cable or Types of Network Connections 21 22 Chapter 2 other high speed services but they re convenient because there s a POTS telephone line in just about every home and business and because the PTSN often continues to work during power failures A network connection through a telephone line uses a modem to convert digital computer data to sounds that can pass through the PTSN A second modem at the other end converts those sounds back to digital data The communications programs in Windows and other operating systems send control codes that instruct the modem to transmit telephone numbers and adjust the data transfer speed and other configuration settings Most new laptops have built in PTSN modems Separate modems for desktop computers are available as internal expansion cards or external devices that connect to the computer through a serial data port or a USB cable Figure 2 9 shows the dial up modem control panel used in Windows XP to connect a computer to a distant network or an Internet service provider ISP Figure 2 10 shows the setup screen for the HyperTerminal program Other programs have different layouts but they all do essentially the same thing They dial a telephone number and log in to the computer that answers the call Advanced properties specify the type of network connection the data speed and other configuration settings Connect Internet via MS
381. w account in the Manage Accounts dialog Step through the rest of the process to create a new account and then return to the File Sharing dialog You should now see the name of the new account in the drop down menu Select the person you want to share access to this folder with and click the Add button That name will appear in the list of users as shown in Figure 12 8 ry kw 72 File Sharing Choose people to share with People without a user account and password for this computer can access files you share with everyone To change this setting use the Net Name Permission Level R Everyone amp john Ross Owner v 3 Sample New User Reader 4p Unknown Contact Co owner Wt Share Cancel Figure 12 8 The File Sharing dialog now includes the new user s name 7 Click the Permission Level to the right of each user s name to assign that person one of these permissions for the shared files in this folder Reader A reader can view the contents of files but cannot edit or delete them Contributor A contributor can view files and add new ones to the folder but cannot edit or delete existing files Co owner The co owner of a file or folder can open and view files create new ones and edit or delete existing files 8 Click the Share button at the bottom of the dialog to save your changes and close the window 9 The File Sharing utility will display a window confirming that the folder in question is no
382. w shared with other computers on the network The utility offers to email other users to advise them about the new shared folder but you do not need to send such a message the new share automatically appears whenever an authorized user opens a link to your computer as shown in Figure 12 9 T Tower Computer Tower Bl xj File Edit View Favorites Tools Help 2 Or Ory FIDE lee xX lbr ig Address 2 Tower 2 2 2 Ampex Manuals C F Folk Music Revival ad ad ed a G H Hootenanny Pix Public 8 objects A Figure 12 9 This network link shows a computer with four hard drives C F G and H along with three shared folders and a Public folder 10 Click the Done button at the bottom of the dialog to close the window To change permissions for an individual file within a shared folder follow these steps 1 Open the folder that contains the file 2 Right click the name or icon for the file whose permissions you want to change A Properties window for that file will appear Sharing Files Through Your Network 141 142 Chapter 12 Click the Security tab to view the dialog shown in Figure 12 10 In the Group or User Names list choose the name of each user to see current permissions If you can t see the name you want use the scroll bar at the right side of the list To change a user s access to this file click the Edit button The Permis sions dialog shown in Figure 12 11 will appear i JI
383. when you re using existing circuits such as telephone lines you don t have any choice you must find a way to send one bit at a time with some additional bits and pauses that identify the beginning of each new byte This is a serial data communications channel because you re sending the bits one after another At this stage it doesn t matter what medium you use to transmit those bits it could be electrical impulses on a wire or two different audio tones or a series of flashing lights or even a lot of notes attached to the legs of carrier pigeons but you must have a way to convert the text or other output of the computer to the signals used by the transmission medium and to convert the same signals back again at the other end Packets and Headers Communication over a direct physical connection such as a wire between a single origin and destination doesn t need any kind of address or routing information to tell a message where to go You might have to set up the connec tion first by placing a telephone call or plugging cables into a switchboard but after you re connected the link remains in place until you instruct the system to disconnect This kind of connection is great for voice and for simple data links but it s not particularly efficient for digital data on a complex net work that serves many origins and destinations because a single connection ties up the circuit all the time even when no data is moving through the channe
384. wireless service you can connect through that network to the Internet and onward to your corporate VPN server Because you ll have to log in to the public network before you initiate the VPN connection you should create a separate VPN via Public Network connection profile in addition to the one you use from your own office The profile should point to your corporate VPN server but it should not be your default connection To connect through a public network on a computer running Windows follow these steps 1 Turn on the computer with the wireless network adapter in place 2 Use your wireless configuration utility to select the public network you want to use 3 Start Internet Explorer Netscape Navigator or another web browser You will see the public network s login screen 4 Ifthe computer doesn t do it automatically type your account name and password The public network will acknowledge your login 5 Minimize the browser window and open the Network Connections win dow or find the VPN shortcut on your desktop 6 Double click the icon for your VPN via Public Network profile The com puter will connect through the Internet to your corporate LAN 7 Type the login and password for your corporate network Network Security 173 174 VPNs are an important part of many networks security plans for off site users With just a few keystrokes or mouse clicks you can establish access to your network resources from anywhere wi
385. work If you can t connect to any site look for a local problem such as your computer the LAN or your Internet service provider An Alternate Connection to the Internet When your Internet connection breaks down it s not possible to use that connection to consult technical support websites or send email to your net work provider Therefore it s often helpful to have a backup method for connecting at least one of your computers to the Internet It might be a neighbor s Wi Fi network with their permission of course a nearby library or coffee shop that offers Internet access or a link through a dial up tele phone line and modem Before you have a problem ask your Internet service provider if they offer dial up access along with their high speed services If they do ask them for a dial up account as an emergency backup and make a note of the access telephone numbers login name and password in your network notebook The Collective Wisdom of the Internet Any problem that occurs on your network has happened before to somebody else You have an excellent chance of finding a description of the problem and instructions for fixing it someplace on the Internet This is where defining the problem carefully becomes important If you re working with a Windows based network the Microsoft Knowledge Base at hitp support microsoft com can be particularly useful if Microsoft s technical support people have ever had to deal with a part
386. work Connection Properties X Travelodge Palo Alto properties General Wireless Networks Advanced below Available networks v Use Windows to configure my wareless network setings To connect to disconnect fom or find out more information about wireless networks in range click the button below View Wireless Networks Preferred networks Automatically connectto available networks in the order listed 4 Travelodge Palo Alto Automatic Stanford Manual 4 test Aulomate X SampleNetwork Automatic Add Remove Properties Leam about seting up wireless network configuration Advanced Association Authenlicabon Connection Network name SSID Wireless network key This network requires a key for the following Network Authenscaton x Data encryption WEP Y Network key DIDI Co coe Figure 8 8 The Windows Wi Fi control program automatically saves the characteristics of past network connections If your computer remains connected to the same Wi Fi network all the time at home or in your office or if you frequently connect to the same Wi Fi hotspot at your favorite coffee shop or lecture hall the Wi Fi control program should automatically use the password and other configuration settings for that network every time you turn on the computer within the network s range The exceptions are public networks that require a new login with every connection N
387. work data because they see the data as noise on the AC power voltage Conversely if you re using a powerline net work you will want to connect your stereo or home theater system to power conditioners to filter out the noise produced by the network All equipment that follows the HomePlug specifications should work together in the same network Some older types of powerline networking might also be available but they re less reliable than HomePlug because they can suffer from interference caused by certain electrical appliances such as vacuum cleaners and other appliances that use big motors or power transformers and they don t always work well with very old house wiring Today it s better to stay away from anything that doesn t carry the HomePlug certification mark shown in Figure 2 4 Pratt HomePlug CERTIFIED Figure 2 4 The HomePlug certification mark indicates that a powerline network ing product has been approved by the HomePlug Powerline Alliance If installing Ethernet wiring is not practical in your building a HomePlug network might be your best choice When it works which it does in most houses it provides an easy reliable network But some would be users report slow performance and other problems so it s best to buy your HomePlug adapters from a retailer who will allow you to return them if they don t work in your house Other Alternative Wiring Methods Two more home networking methods are po
388. works If you plan to connect the computer to a Gigabit Ethernet network you ll need a faster and more expensive adapter Like other computer components Ethernet adapters are available both as inexpensive no name products and slightly more costly brand name versions that come with better documentation and a manufacturer s warranty As always you get what you pay for considering that you can generally find a brand name adapter for just a few dollars or euros or pounds more it s usually the better choice Internal Expansion Cards Internal network adapters are printed circuit cards that fit into one of the expansion slots on your computer s motherboard like the one shown in Figure 7 3 Unless you re working with a very old computer the adapter should be a PCI card that s probably the only kind you will find at your local computer or office supply store The PCI sockets on the motherboard are almost always white Photo courtesy of D Link Figure 7 3 An internal PCI card mounts in an expansion slot inside a desktop or tower computer If your computer was made before the mid 1990s you might need an ISA card instead ISA sockets on motherboards are usually black ISA Ethernet adapters are still available but you ll probably have to go to a specialist source A Web search for ISA Ethernet card will produce pointers to many choices but be sure to order a 10 100 or fast Ethernet card rather than an older design that works at only
389. works in their computers control programs Channel number Each access point operates on a single channel This option sets that channel For best performance choose a channel that is different from the ones used by other Wi Fi networks within your signal range Operating mode Many access points can operate on more than one operating mode 802 11b 802 11a 802 11g or 802 11n depending on the mode used by the computers with which it exchanges data This option allows you to set the access mode to detect operating modes automatically and choose the best one available or to specify a parti cular mode Other wireless settings are often available sometimes in a separate advanced menu or web page Unless you have a good reason to change something it s usually best to keep the default settings Many Wi Fi access points are combined with routers or modems so the configuration process also includes some additional setup options See Chapter 10 for information about configuring a router or modem If you re using a separate access point it s usually best to turn off the DHCP server in the access point and obtain all of the network s addresses from the router or modem Wireless Connection Programs A computer with an installed Wi Fi adapter uses a wireless control program to select a Wi Fi network and establish a connection Windows Mac OS X and various versions of Linux and Unix include wireless control programs and alternative control
390. ws you to select files from your own server or streaming programs through the Internet Ultimately these devices will be as easy to use as the tabletop radio in your bedroom or kitchen simply turn the device on select the station and listen The important difference is that you re not limited to the programs on local radio stations you can choose from thousands of radio stations and streaming music services that offer a huge variety of music news and other programming many of them without commercials Today Internet radios are still expensive novelties most cost 200 or more but if and when the price comes down they will probably become a hugely popular alternative to radios that only receive local stations Video Through a Home Network Video in the form of movies television shows home videos or files down loaded through the Internet is yet another type of program material that you can distribute through your network You can view videos on your computer s monitor or through an adapter on a television screen Video distribution through a network follows a similar structure to audio Video files are stored on a server and transmitted to a client on demand However video files contain many more bits per minute of content than audio files so the network must have a high enough capacity to handle that additional demand In practice this means that many Wi Fi links except the newest 802 11n equipment may not be able to keep u
391. xchange data in both directions between these two networks In certain respects the Internet treats the router the same way that the router treats the other com puters on the network but the Internet uses different addresses to accomplish those goals One of the important activities that occurs inside the router is network address translation Your router s Setup utility shows two groups of settings one for the WAN and one for the LAN The WAN side identifies the router to the Internet with a unique numeric address That address can be either fixed or static which means that it is always exactly the same or dynamic which means that a server at the WAN assigns the next available address from a pool every time the router connects to the WAN Dynamic address assignment uses a process called Dynamic Host Configuration Protocol DHCP which is described in DHCP Servers On or Off on page 110 The gateway router typically specifies the numeric address of one or more Domain Name System DNS servers that convert Internet addresses that use words such as nostarch com into numeric addresses Without a DNS server to consult the WAN won t know where to direct email messages requests for web pages or any other attempts to communicate with a destination on the Internet Your Internet service provider will provide the addresses of one or more DNS servers The router also needs a gateway address and a subnet mask The gateway is the next router in li
392. y a Network Setup Complete screen Connecting to a Wireless Network To connect a TiVo DVR to your network through a Wi Fi link follow these steps 1 Press the TiVo button on your DVR The TiVo Central screen will appear Select Messages and Settings gt Settings Phone amp Network If your TiVo is already connected to a telephone line select Use network instead If it s connected to a wired network select Change network set tings Press Select If the wireless adapter is not already connected connect it now When the TiVo identifies the wireless adapter it will display the Network Adapter Detected screen Press Select The Wireless Network Name screen will appear Either select the name of your Wi Fi network and press Select or if the network does not broadcast the network s name select Enter network name and follow the instructions on your screen TiVo will ask for your network password Use the keypad on your screen to type your WEP or WPA password and then click Done Entering Net work Password If the password is correct and your network uses a DHCP server the Network Setup Complete screen will appear If the network doesn t use DHCP you will see a series of configuration screens Type the IP address subnet mask and the addresses for your network s gateway router and DNS server Importing Programs To watch a program that has been stored on a TiVo from a second DVR in another room follow these steps
393. y detect your network If you don t take some precautions to prevent it your neighbor or somebody using a laptop or PDA inside a car parked on the street can log in to your LAN steal files from your servers and tie up your Internet connection with streaming videos multiplayer games or worse It s important to understand that we re talking about two different kinds of security threats The first is the danger of an outsider connecting to your network without your knowledge or permission the second is the possibility that a dedicated eavesdropper can steal or modify data as you send and receive it Each represents a different potential problem and each requires a different approach to prevention and protection While it s certainly true that none of the encryption tools currently available can provide complete protection they can make life more difficult for most casual intruders And as long as the tools are out there you might as well use them Network Security 175 176 Chapter 13 An unsecured wireless network presents many opportunities to an attacker Not only are the network crackers able to monitor any data that moves through the network but they might also be able to modify that data If for example your web browser has a vulnerability an attacker can replace images as you view them with an image that exploits that vulnerability and installs a Trojan horse program on your computer allowing the attacker to steal data st
394. y increases the key s complexity a long key takes much longer to crack than a short one However a commercial product called Elcomsoft Distributed Password Recovery uses graphics processors on video cards to break Wi Fi encryption up to 100 times faster than by using CPU only so even a relatively long key is not that secure Completely protecting yourself against attacks might not be possible or practical but a long passphrase that includes random numbers and punctua tion marks is still a better choice than a string of words or numbers alone Network Security 183 184 In other words something like hdt 96mzx33wolfbfgilxxqcv ttsmedbxoris a better passphrase than nostarchpressbooks But the only truly secure way to use Wi Fi is to combine it with VPN encryption Access Control MAC Authentication Most access points include an option that permits the network manager to restrict access to a specific list of client adapters If a network device with a MAC address that does not appear on the list of authorized users tries to connect the access point will not accept the request to associate with the network This option can keep intruders from connecting to a wireless LAN but it forces the network administrator to keep a complete list of users adapters and their MAC address Every time a new user wants to join the network and every time an established user swaps adapters or gets a new laptop PDA or other device with a built in a
395. your computer against security threats and performance problems we strongly recommend Updates 1 you install all high priority updates Select b i Total 1 updates 171 KB less than Type y Review and install updates miniis High Priori ar Y 4 Important Software You ve hidden important updates Optional 2 You ve asked us not to show you one or more high priority updates but your computer might be at risk until they are installed Restore them now Hardware Optional 0 Select by High priority updates oe Microsoft Windows Defender Windows 3 ra I CAPICOM Definition Update for Windows Defender KB915597 Definition 1 39 119 0 0 E Microsoft Update Privacy Statement 2008 Microsoft Corporation All riahts reserved Terms of Use Trademarks Privacy TT T T T inem 100 gt 5 Figure 13 21 The list of update types left shows the number of updates available for each category Network Security 187 188 5 Choose the updates you want to install in each category from the right panel The number in parentheses next to Install Updates in the left panel shows the number of updates you have selected 6 Click Install Updates The Review and Install Updates panel will appear on the right side of the window 7 Click the Install Updates button The update program will load the updates you have selected one at a time If necessary the Update rou tine will restart the computer to complete one

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