Troubleshooting the Computer Browser Service with - DESY
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1. number of master browsers and backup browsers can be numerous and a source of considerable network traffic In turn these local master browsers on each subnet exchange lists with the domain master browser server which is also the Windows NT Primary Domain Controller PDC for that domain Any Solaris PC NetLink software server Windows NT Server or Workstation Samba server and even Windows 95 amp Windows 98 systems in some cases can potentially function as a subnet s master browser server Unlike WINS DNS DHCP and other network services where the system administrator usually defines what server the service runs on the master browser server is chosen through an automated multi round election process This process can occur frequently on a busy LAN as servers and PC Clients reboot and establish their presence Many network events can force a new election process on the subnet causing significant network traffic and anomalous events which can baffle end users as well as system administrators Neither the end user requesting information from the service nor the system administrator may even be aware of this process occurring By default all Solaris PC NetLink software Samba Servers Windows NT 98 and 95 systems are enabled to potentially become a master browser server for a subnet This election process occurs by a set of rules see Section 6 8 Browser Elections of the computer browser specification listed in reference section be2. GARANTIE EXPRESSE OU IMPLICITE N EST ACCORDEE Y COMPRIS DES GARANTIES CONCERNANT LA VALEUR MARCHANDE L APTITUDE DE LA PUBLICATION A REPONDRE A UNE UTILISATION PARTICULIERE OU LE FAIT QU ELLE NE SOIT PAS CONTREFAISANTE DE PRODUIT DE TIERS CE DENI DE GARANTIE NE S APPLIQUERAIT PAS DANS LA MESURE OU IL SERAIT TENU JURIDIQUEMENT NUL ET NON AVENU Trouble shooting Computer Browser Service with Solaris PC NetLink Software S ca Please Adobe PostScript Recycle Troubleshooting the Computer Browser Service with Solaris PC NetLink Software The purpose of the Computer Browsing Service is to offer a mechanism by which PC Clients can display shared disks printers and other resources available on a local network The computer browser service not to be confused with internet browsing was first implemented in Microsoft Windows 3 11 to support browsing on small subnets This service relied heavily on the ability of PC Clients to acquire the information they required directly on the subnet to which they are attached Early in it s use the popular protocol to use on local hubbed LANs of the time was NetBIEU This protocol has a well understood scaling limitation in that it does not function across subnets Enterprise network environments have matured and now the TCP IP protocol helps enable networks to scale well beyond the simple subnet environments of LANs of the past The current computer browser service which all current Microso
3. LEE Cr Dr Troubleshooting the Computer Browser Service with Solaris PC NetLink Software By Don DeVitt Enterprise Engineering Sun BluePrints OnLine April 2000 microsystems ENTERPRISE ENGINEERING http www sun com blueprints Sun Microsystems Inc 901 San Antonio Road Palo Alto CA 94303 USA 650 960 1300 fax 650 969 9131 Part No 806 5331 10 Revision 01 April 2000 Copyright 2000 Sun Microsystems Inc 901 San Antonio Road Palo Alto California 94303 U S A All rights reserved This product or document is protected by copyright and distributed under licenses restricting its use copying distribution and decompilation No part of this product or document may be reproduced in any form by any means without prior written authorization of Sun and its licensors if any Third party software including font technology is copyrighted and licensed from Sun suppliers UNIX is a registered trademark in the U S and other countries exclusively licensed through X Open Company Ltd Sun Sun Microsystems the Sun logo Sun BluePrints and Solaris are trademarks or registered trademarks of Sun Microsystems Inc in the U S and other countries All SPARC trademarks are used under license and are trademarks or registered trademarks of SPARC International Inc in the U S and other countries Products bearing SPARC trademarks are based upon an architecture developed by Sun Microsystems Inc The OPE
4. N LOOK and Sun Graphical User Interface was developed by Sun Microsystems Inc for its users and licensees Sun acknowledges the pioneering efforts of Xerox in researching and developing the concept of visual or graphical user interfaces for the computer industry Sun holds a non exclusive license from Xerox to the Xerox Graphical User Interface which license also covers Sun s licensees who implement OPEN LOOK GUIs and otherwise comply with Sun s written license agreements RESTRICTED RIGHTS Use duplication or disclosure by the U S Government is subject to restrictions of FAR 52 227 14 g 2 6 87 and FAR 52 227 19 6 87 or DFAR 252 227 7015 b 6 95 and DFAR 227 7202 3 a DOCUMENTATION IS PROVIDED AS IS AND ALL EXPRESS OR IMPLIED CONDITIONS REPRESENTATIONS AND WARRANTIES INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY FITNESS FOR A PARTICULAR PURPOSE OR NON INFRINGEMENT ARE DISCLAIMED EXCEPT TO THE EXTENT THAT SUCH DISCLAIMERS ARE HELD TO BE LEGALLY INVALID Copyright 2000 Sun Microsystems Inc 901 San Antonio Road Palo Alto Californie 94303 Etats Unis Tous droits r serv s Ce produit ou document est prot g par un copyright et distribu avec des licences qui en restreignent l utilisation la copie la distribution et la d compilation Aucune partie de ce produit ou document ne peut tre reproduite sous aucune forme par quelque moyen que ce soit sans l autorisation pr alable et crite de Sun et de ses baill
5. Services Browser Parameters MaintainServerList REG_SZ false Readback value from registry echo Setting MaintainServerList parameter to false echo New MaintainServerList parameter should now be false opt lanman sbin regconfig SYSTEM CurrentControlSet Services Browser Parameters MaintainServerList Troubleshooting the Computer Browser Service with Solaris PC NetLink Software 5 Solaris PC NetLink software must be stopped and started for the above change to become effective Plan to reset Solaris PC NetLink software when no one is using it The above change does not affect the Solaris PC NetLink software ability to act as a local WINS server Samba Servers Allowing all versions of Samba to become a master browser server is problematic for the following reasons a AT least with older versions Samba will force the master browser election process to choose the Samba server This can cause some browsing functionality to not work in some instances m Samba servers can not fully participate as a PDC or BDC in a Windows NT domain Because of this and other reasons it does not always work correctly for browsing Windows NT domains servers To turn off Samba s ability to become a master browser or to help diagnose a browser s problem you can disable Samba s ability to become a master browser by setting the following values in the global section of the Samba smb conf file domain master no
6. and when the domain will no longer be seen by other domain browsers and browsing clients m It can take up to 36 minutes before the removal of a system from a network is registered by the local browse master a It can take up to 51 minutes for changes such as the addition or removal of a domain member client before they can be seen on another subnet browse masters It can take up to 66 minutes for a change in a local subnet to be reflected across the network Delays like these can cause significant frustration especially if you are not aware that they exist For example if a server is off line for 30 60 minutes and then comes back on line it may look like it is still down for a considerable period of time if users attempt to access the server via the browser mechanism Browsing does not need to be fully functional for users to access file and print services on a server As a work around users can always explicitly access server shares on Solaris PC NetLink software by mapping a network drive using a full path name such as server name shar 1 Data from Samba Integrating Unix and Windows John Blair Troubleshooting the Computer Browser Service with Solaris PC NetLink Software 3 Maintaining a WINS Server For browsing to list systems on anything but the local subnet successfully NetBIOS name resolution must exist to resolve names of systems on non local subnets The only mechanism that can support the special names needed by the b
7. duced over the last 13 years Don started his career as an Electrical Engineer and has worked in the Automated Test industry for Teradyne Inc and in the PC operating system market for Digital Research from CP M frame before coming to Sun Trouble shooting Computer Browser Service with Solaris PC NetLink Software April 2000
8. eurs de licence s il y en a Le logiciel d tenu par des tiers et qui comprend la technologie relative aux polices de caract res est prot g par un copyright et licenci par des fournisseurs de Sun UNIX est une marque d pos e aux Etats Unis et dans d autres pays et licenci e exclusivement par X Open Company Ltd Sun Sun Microsystems le logo Sun Sun BluePrints et Solaris sont des marques de fabrique ou des marques d pos es de Sun Microsystems Inc aux Etats Unis et dans d autres pays Toutes les marques SPARC sont utilis es sous licence et sont des marques de fabrique ou des marques d pos es de SPARC International Inc aux Etats Unis et dans d autres pays Les produits portant les marques SPARC sont bas s sur une architecture d velopp e par Sun Microsystems Inc L interface d utilisation graphique OPEN LOOK et Sun a t d velopp e par Sun Microsystems Inc pour ses utilisateurs et licenci s Sun reconna t les efforts de pionniers de Xerox pour la recherche et le d veloppement du concept des interfaces d utilisation visuelle ou graphique pour l industrie de l informatique Sun d tient une licence non exclusive de Xerox sur l interface d utilisation graphique Xerox cette licence couvrant galement les licenci s de Sun qui mettent en place interface d utilisation graphique OPEN LOOK et qui en outre se conforment aux licences crites de Sun CETTE PUBLICATION EST FOURNIE EN L ETAT ET AUCUNE
9. ft Operating systems and thus Solaris PC NetLink software support evolved from this legacy The Solaris PC NetLink software now shares the issues brought about in supporting this service This article offers several suggestions on how to troubleshoot situations when this service appears to be not functioning properly How Solaris PC NetLink Software Supports the Computer Browsing Service A full explanation of the computer browser service is not possible in this on line article Instead I will give a brief explanation of how the computer browser mechanism works in the context of Solaris PC NetLink software operation The reader should consult the references at the end of the article for a more in depth understanding of the browser mechanism Computer Browsing The computer browsing lists are supported on each subnet by a server know as a master browser There will be one master browser for each Windows NT domain or workgroup and sometimes many systems acting as backup browsers that maintain resource lists in the event that the master browser goes down In addition to having one master browser for each domain there may be a master browser for each domain on each transport protocol used to support the domain If a Windows NT server were to support the three most popular protocols TCP IP NetBEUI IPX SPX there may be up to three master browsers on each subnet for that domain If multiple domains are supported on a subnet the possible
10. hat can occur is when due to the election process the master browser for a protocol is moved from one server to another The new server may not have the same lists established as the older master browser The effect of this shuffling of servers is that users on PC Clients may see systems disappear from their Network browser To minimize the number of elections that occur and thus the network traffic and delays it is highly advisable to remove protocols that you know you will not be using It would be best if all systems used only the TCP IP protocol TCP IP is the most scalable protocol it is also the protocol that must be used to access the internet and enterprise intranets today If at all possible remove all other protocols such as NetBIEU and IPX SPX Check with the local network administrator to see if there are any other servers or services that must use these additional protocols Removing network protocols is accomplished by using the Network icon on the control panel of Windows based PCs Tools to Monitor the Master Browser Several tools may be useful in monitoring the master browser for a domain Solaris PC NetLink software can supply some browser related information by way of the opt lanman bin net browser command Windows operating systems have a command line tool called nbt stat The command nbtstat a lt adapter gt supplies name tables available on servers The Windows NT Server Resource Kit offers a command line executable k
11. is because the browse master can not be sure that the systems requesting browser lists on one subnet can access the other subnets To circumvent this problem we suggest that you disable any server that has two or more network connections from becoming a browse master for any subnet With Solaris PC NetLink software this can be accomplished by setting the Solaris PC NetLink software registry value MaintainServerList to false or no See the article referenced above While you can set this value of this parameter via Windows NT regedt 32 program we suggest that you maintain a master script of registry changes so there is a record that the change has been made to your server A best practice article on the Sun BluePrints OnLine site covers maintaining a master registry change script See Managing the Solaris PC NetLink Registry available at URL http www sun com blueprints 0200 managing pdf The segment of the script that will make this change should look like this This server serves two subnets Turn off the capability of it being a Master Browse See Microsoft Knowledge base article 0191611 echo Old MaintainServerList Value OK to have no Parameter yet opt lanman sbin regconfig SYSTEM CurrentControlSet Services Browser Parameters MaintainServerList Set MaintainServerList value to false echo Setting MaintainServerList parameter to false opt lanman sbin regconfig SYSTEM CurrentControlSet
12. local master no preferred master no os level 0 Imhosts files System administrators occasionally use 1mhosts files C WINNT system32 drivers etc lmhosts on Windows NT systems C windows lmhosts on Windows 95 amp 98 systems to temporarily resolve host name issues If these are left with old information their values will override values that may be returned from a WINS server Make sure that if these file must be used that they have the correct values for host names For normal operation it is best to use only a WINS server to resolve NetBIOS names to avoid any conflict 6 Trouble shooting Computer Browser Service with Solaris PC NetLink Software April 2000 PC Clients with Multiple Network Protocols When multiple network protocols are running on a PC Client the browsing mechanism can create extensive network traffic and produce significant delays as the PC Clients attempt to use all protocols to perform the browser operation In this situation there may be a master browser for every network transport protocol as mentioned above Solaris PC NetLink software supports only the NetBIOS over the TCP IP protocol The presence of additional protocols on a PC Client can cause significant delays during the browsing process as each master browser for each protocol is determined and queried The election process caused by PC Clients and servers with these additional protocols can take considerable time One anomalous condition t
13. low and can take considerable time before the master server has been elected and has up to date lists of servers and services from its own subnet and the domain master browser server 2 Trouble shooting Computer Browser Service with Solaris PC NetLink Software April 2000 the PDC The election process alone can account for many delays experienced by users of PC Clients as they attempt to use the Network Neighborhood icon on their PC Clients to browse their way to a shared file system on a server Attempting to browse your way to a service during the recovery period after a power failure can be a very frustrating experience Diagnosing Browser Service Problems When the browse service fails or suffers considerable delays it is sometimes difficult to diagnose the problem What follows is a procedures and tools that can be of help when diagnosing a browser problem where the Solaris PC NetLink software is involved Delays in Viewing Changes by Browsing Changes that occur on the network take a long time before they can be seen by browsing In addition the protocol that governs how changes in the network are propagated to browse masters has many built in delays Under worse case scenarios the following delays can be seen between the time that a change occurs in the state of the network and the time that the change can be seen while browsing a It can take up to 45 minutes before a PDC also the domain master browser is shut down
14. n be configured to be a WINS server m Are all the PC Clients configured to use a common WINS server Check the WINS Configuration Tab in the TCP IP properties of the Network configuration of the PC Client to make sure that it is using a common WINS server Alternately the DHCP server can be used to supply the WINS server configuration m Is the WINS server up and running m Is the master browser for the subnet attached to two subnets The next section deals with this issue fully Servers with Two or More Network Connections If a PC Client attempts to browse using a master browser in the form of a Solaris PC NetLink server that is attached to two or more subnets or any Windows NT multi homed server the PC Client will only be given lists of the resources for the subnet it is a part of Resources on the other subnets supported by the server will NOT be seen The Microsoft Knowledgebase has a complete write up of this problem that 4 Trouble shooting Computer Browser Service with Solaris PC NetLink Software April 2000 exists for all Windows NT systems Please refer to the document found at http support microsoft com support kb articles Q191 6 11 ASP or search the Microsoft Knowledgebase for Q191611 In summary a browse master will maintain a separate browse list for each subnet to which it is attached It will only supply the list of resources for the subnet from which the browse request was made The reason for this
15. nown as browstat and a GUI based tool called browmon The browman tool is the easiest to use for giving the most information on browser related information Troubleshooting the Computer Browser Service with Solaris PC NetLink Software 7 References For additional detailed information on Solaris PC NetLink software refer to the Sun BluePrints book Solaris PC NetLink Software Performance Sizing and Deployment ISBN 0 13 026686 8 which is scheduled for publication by Prentice Hall in the May of 2000 and is expected to be available through www sun com books amazon com fatbrain com and Barnes amp Noble bookstores The Samba web site has information about using Samba as a browse master See http usl samba org samba ftp docs textdocs BROWSING The specification for the browser service can be found at ftp ftp microsoft com developr drg cifs cifsbrow doc The Microsoft Windows NT Server Network Guide from the Windows NT Server Resource Kit is a also good source of information for understanding the browsing mechanism 8 Author s Bio Don De Vitt Don DeVitt is a PC Interoperability specialist and Senior Staff Engineer within the Enterprise Engineering group at Sun Microsystems Don is also a member of the Sunlink Server engineering team where he has focused on performance related issues Don has been on the development teams of almost every software and hardware PC Interoperability product that Sun Microsystems has pro
16. rowser service is to use a WINS server A Solaris PC NetLink server can be configured to fully support the WINS service WINS is what is used by the master browsers to register the Domain Master Browser names required to support the browsing on other subnets Master browsers on the local subnet to a PC can be found by way of broadcasts The domain master browser also the PDC of the domain collects and redistributes all the servers and services information from all the master browsers on all the subnets where there exists a server or PC Client that is a member of the domain Master browsers for a subnet can find the domain master browser by sending a query to their WINS server to resolve the special NETBIOS name lt DomainName gt 1b Hex This special NETBIOS name consists of the Windows NT domain name that the PC Client is a member of with 1b Hex in the last 16 byte position Once the domain master browser is determined from the WINS server the local master browser can find all of the browse information for the domain quickly and help enable browsing to proceed quickly If no WINS service is available the process can take considerable time for the required time outs to occur in determining the local subnets master browsers by other means If you are experiencing a situation where only the systems on the local subnet are seen during browsing the first things to check are m Is there a WINS server established The Solaris PC NetLink software ca
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