jSNMP Enterprise™ FAQ
Contents
1. For JDK1 2 and JDK1 3 you can follow the instructions for JDK1 1 or you can run jMIBC without setting the CLASSPATH environment variable For example this can be accomplished with the following command java jar jMIBC jar options lt mibfile gt The jar flag tells the Java interpreter that the application is packaged in the JAR file format Q Can we use the parsing capabilities of the jMIBC in order to use it for showing a MIB tree in an SNMP MIB browser that we write Does the SnmpMIBService export the MIB tree that is parsed A The SnmpMIBService is used to resolve OIDs to object names and enumerated names to enumerated values and vice versa With a simple walk of an agent you can build a tree of OIDs and names You can export that to the database of your choice Q Do jMIBC and the jMIBC loadMib method support SMI version and version2 MIBS A Yes Q Do jMIBC and the jMIBC loadMib method parse the IMPORT section of the MIB module and include all the required MIBs A Yes if the required MIBs are available iMIBC Errors Exceptions and Other Issues Q Why did get the following error Error Unknown syntax of lt type gt for lt name gt in lt file gt A This message will be displayed if an object has a syntax type that has not been declared The recommended way to handle this error is to include all dependent MIB files Q Why did get the following error Error lt name gt from lt file gt is2. When an SnmpCustomer deliverSuccessfulOrder method delivers an SnmpVarBind object the varBind value can be retrieved via its get Value method and its type can be determined by its get Type method OCTET STRING SnmpConstants ASN_OCTSTR type objects are represented as byte Cast the object returned by getValue method with byte If your physical address value is represented by a base SNMP object other than an OCTET STRING you will have to appropriately cast the object returned by the getValue method Copyright 2003 jSNMP Enterprises All Rights Reserved 3 Q I want to make requests with object names rather than OIDs How do I go about it A jSNMP 3 x has the ability to use RFC1213 MIB MIB II object names The example application SnmpV1GetSyslInfo java illustrates how to retrieve the RFC1213 MIB objects sysName sysContact sysLocation ifDescr and ifAdminStatus as well as load the HOST RESOURCES MIB my MIB file at runtime and retrieve the HOST RESOURCES MIB objects hrSystemUptime hrSystemDate hrSystemlInitialloadDevice hrSystemInitialLoadParameters hrSystemNumUsers hrSystemProcesses hrSystemMaxProcesses and hrMemorySize This application illustrates the use of the SnmpMIBService interface which can be used to translate OIDs to from common names to retrieve an OID s status access type abstract type and description and to translate OID enumerated values To use the SnmpMIBService interface please re
3. 3 1 1 5 1 you are correctly specifying the OID and trap number When you receive traps with an enterprise OID of 1 3 6 1 6 3 1 1 5 the trap type will be zero based Other enterprise OIDs trap types will be one based iSNMP Errors Exceptions and Other Issues Q I m using jSNMP within an applet Why does the browser throw a SecurityException when try to communicate with an SNMP device A As of version 2 01 jSNMP Enterprise is capable of running in either Netscape Communicator 4 5 or Microsoft IE 4 01 or later versions Security issues are still possible though depending on how your applet is packaged for the web Java security restrictions inside browsers prevent untrusted applets from calling various Java APIs These APIs include many networking calls required to do SNMP Enabling an applet to run ina browser environment generally involves the following two steps 1 allow the applet to be trusted either by packaging it in a signed archive JAR or CAB or placing it on the local CLASSPATH 2 call vendor specific APIs to grant the required rights to the applet For more information on applet security see Sun s Frequently Asked Questions Java Security or Netscape s Security Documentation Example applets are included in jSNMP Enterprise which demonstrate jSNMP based applications within a browser Q When tried to compile the SnmpV1GetSysinfo java application I got the following error Exception in thread main java lang
4. IDL mapping Q I just generated the CORBA stubs why would I use the included Java Client to communicate with the remote jSNMP service instead of talking directly through the stubs A To make accessing the remote jSNMP services easier for Java developers we ve included a Java wrapper to the CORBA Client This provides Java developers an easy way of incorporating the distributed jSNMP CORBA services in their applications without learning all the intricacies of CORBA development One of the great benefits of the Java CORBA Client is that it exposes the same interfaces as the local call jSNMP service The Enterprise developer can therefore use the same code to access local or remote instances of the jSNMP service Q Does the Java Client use CORBA A Yes but you will still need to compile the SNMP IDL to generate stubs compatible with your ORB Copyright 2003 jSNMP Enterprises All Rights Reserved 15 Q What ORBs does jSNMP Enterprise Support A jSNMP Enterprise uses the standard IDL to Java mapping which should allow it to work correctly with any ORB that supports this standard SNMP Enterprise 3 x has been tested successfully with Sun s JDK 1 3 ORB While jSNMP Enterprise 2 x was tested with Inprise s VisiBroker 3 x and lona s OrbixWeb 3 x Sun s JDK 1 3 ORB is the only ORB currently supported by jSNMP Enterprises Q Do I need to be a CORBA developer to use jSNMP Enterprise A We provide the remote Java interface
5. NoClassDefFoundError SnmpV1GetSysinfo What did I do wrong A You are probably having a CLASSPATH problem Make sure that is in your CLASSPATH Q Why do I get the exception NoClassDefFoundError java math BigInteger when using jSNMP A jSNMP requires a JDK1 1 x or newer compliant runtime environment The class java math BigInteger is specific to JDK1 1 and later versions If you are using jSNMP within a browser it must likewise support JDK1 1 x or a later version If you are using Internet Explorer 3 x or Netscape Navigator 3 x you must upgrade to Internet Explorer 4 0 or later or Netscape Communicator 4 x or later Q I received a NULL SnmpVarBind in my SnmpCustomer deliverSuccessfulOrder method What s up A It is possible though rare that an SnmpCustomer deliverSuccessfulOrder method will receive a NULL SnmpVarBind This will happen when a remote agent s response does not contain any varBinds While unlikely jSNMP programmers should test for NULL on the SnmpVarBind argument Copyright 2003 jSNMP Enterprises All Rights Reserved 10 Q I am running the applet developed in my JDKs appletviewer It gives me the following java lang ExceptionInInitializerError java security AccessControlException access denied lt java util PropertyPermission browser read gt The above happens when call SnmpLocallnterfaces getService What s up A You must specifically grant the applet the permissions
6. a session is created the msgAuthoritativeEnginelD is fetched along with the msgAuthoritativeEngineBoots and msgAuthoritativeEngineTime The SnmpV3WalkerTest java example illustrates this behavior Using jSNMP Q Would you please help me with the installation of jSNMP A You should have received a jSNMP zip file as the main distribution All that is required to install SNMP is to unzip it The user s manual will be in the doc directory and will help you getting started Q I see from your examples how to create an SNMP Manager Do you have any examples of how to use your framework from a managed application i e Agent side code using varBinds initiating traps etc A jSNMP Enterprise is a manager only toolkit There is no support for building agents However it does have the ability to send traps and informs Q I am trying to use the SnmpVarBind getValue method I know it returns an Object but don t know how to convert the value received to its equivalent String Please help A Use the SnmpVarBind getStringValue method If you wish to use the object returned by the SnmpVarBind getStringValue method use the SnmpVarBind getType method to retrieve its type The user s manual contains a table that maps the returned type to its Java object type Q I can t extract the values of physical address type from an SnmpVarBind Please help A Physical addresses are traditionally represented as OCTET STRING in SNMP
7. cache to store successful as well as unsuccessful host name resolutions The positive caching is there to guard against DNS spoofing attacks while the negative caching is used to improve performance By default the result of positive host name resolutions are cached forever because there is no general rule to decide when it is safe to remove cache entries The result of unsuccessful host name resolution is cached for a very short period of time 10 seconds to improve performance Under certain circumstances where it can be determined that DNS spoofing attacks are not possible a Java security property can be set to a different Time to live TTL value for positive caching Likewise a system admin can configure a different negative caching TTL value when needed Thus you will have to create a new SnmpAuthoritativeSession and adjust the TTL value for positive caching Copyright 2003 jSNMP Enterprises All Rights Reserved 5 Q We would like to make JSNMP requests synchronously How do we implement blocking requests A While we don t have a specific example for you you will find it quite easy to implement synchronous requests First your SnmpCustomer deliverSuccessfulOrder and SnmpCustomer deliverFailedOrder methods need to call the notify method see http java sun com j2se 1 3 docs api java lang Object html notify and you need to implement the wait method see http java sun com j2se 1 3 docs api java lang Object html wa
8. is scalable to allow many clients to have concurrent access to the jSNMP server In fact benefits of the optimizations made in jSNMP such as combining multiple requests into one network packet are greater when using multiple clients SNMP is able to do all of this and still be highly optimized and scalable much more so than traditional SNMP stacks Q What distinguishes jSNMP Enterprise v3 2 and later from earlier versions of jSNMP A Beginning with version 3 0 jSNMP Enterprise added SNMPv2c and SNMPv3 functionality plus the ability to generate traps and informs jSNMP Enterprise 3 0 also added remote access to jSNMP services via RMI JSNMP Enterprise 3 0 also introduced optimizations to receive large bursts of traps without loss and to allow queries to be made with object names sysContact 0 instead of OIDs 1 3 6 1 2 1 1 4 0 Versions since 3 0 incorporate all of the technology and features in the previous versions Applications written to the interfaces of previous versions of jSNMP will work with the current version but will be limited to making SNMPv1 queries and receiving SNMPv1 traps Q What is jMIBC A Since SNMP Object Identifiers OID are difficult to remember users may prefer to make a SNMP request in a jSNMP Enterprise application with the name associated with an OID instead of the OIDs dotted decimal notation e g fAdminStatus 1 instead of 7 3 6 17 2 1 2 2 1 7 1 JMIBC takes a series of MIB files and produces a d
9. needed to run You can either add the following permissions to your java policy file permission java util PropertyPermission outback trace read permission java util PropertyPermission jsnmp maxClerks read permission java util PropertyPermission jsnmp loadRFC1213MIB read permission java util PropertyPermission jsnmp socketBufferSize read permission java util PropertyPermission jsnmp clerkThreadPool read permission java util PropertyPermission snmp bufferDelay read permission java util PropertyPermission jsnmp cachePrunePerioa read permission java util PropertyPermission jsnmp cacheExpireFloor read permission java util PropertyPermission jsnmp cacheExpireFactor read permission java util PropertyPermission jsnmp cacheDisable read permission java util PropertyPermission snmp trapQueueCapacity read permission java util PropertyPermission snmp trapQueueExpansion read permission java util PropertyPermission jsnmp ignoreV1V2PduSizeLimit read permission java util PropertyPermission jsnmp forceGC read permission java util PropertyPermission jsnmp dumpPackets read permission java util PropertyPermission snmp retrieve TimeStamps read permission java util PropertyPermission snmp retryPacked Timeouts read permission java util PropertyPermission snmp properties read oon permission java util PropertyPermission nocmu
10. of my table is there a way I can tell the SnmpService to stop sending these orders A There is no way to stop a placeGetBulkOrder request or any other request from delivering successful and or failed orders The number of successful failed orders delivered will be determined by the number of non repeater OIDs and repeater OIDs times the number of max repetitions SNMP is designed to guarantee a response for each order requested As you have noticed this can be quite large We suggest that when you walk a table you limit the number of repetitions to a smaller number and make multiple requests until the table walk is finished Q How can I tell when a getBulk request has ended A The placeGetBulkOrder will return a value that is the one more than the last order number that will be passed as the i1OrderNum argument to your deliverSuccessfulOrder and deliverFailedOrder methods All you have to do is wait for order confirmations for all of these orders through your deliverSuccessfulOrder and deliverFailedOrder methods Look at the SnmpV2GetBulkApplet java file in the examples directory of the distribution Q The agent that we are using has a problem accepting more than 24 varBinds in a single set PDU When use the placeSetOrder with more than 24 OIDs jSNMP seems to send them all at once and the agent cannot handle them What should I do A The maximum number of SnmpClerks defaults to 25 which represents
11. MPv3 session it is necessary to do discovery by communicating with the remote agent to establish the remote MTU engine ID boot time and engine time This is the reason it takes some time as it requires 1 or 2 communication passes between your client and agent This will not happen with SNMPv1 v2 sessions It is recommended that sessions be created once and reused as necessary Q Please correct me if am wrong After making a getBulkOrder request jSNMP will report SnmpConstants SNMP_ERR_RESPONSENOTGENERATED for failed deliveries due to the maximum PDU size being reached in the agent A You are correct jSNMP guarantees a response success or not to all outstanding orders With a getBulk request you place non repeaters repeaters repetitions orders Since the agent responds with less than the number of varBinds expected jSNMP reports the SnmpConstants SNMP ERR R ESPONS ENOTG EN ERAT ED error for each of the orders varBinds not received Remember the number of repetitions will vary from agent to agent and at what point the repeater starts in the MIB due to the PDU size limit of each agent Reaching the end of a MIB with a getBulk request has a similar but slightly different behavior When reaching the end of a MIB with a getBulk request your deliverFailedOrder method will receive a SnmpConstants SNMP_ERR_ENDOFMIBVIEW error for the first varBind past the end of the MIB an
12. NMP examples classes export JAVA_HOME usr java jdk1 3 0_02 jre export PATH JAVA_HOME bin PATH export CLASSPATH SNMPEnterprise jar JAVA_HOME lib ext jice1_2_1 jar JAVA_HOME ib ext sunjce_provider jar JAVA_HOME lib ext ocal_policy jar JAVA_HOME ib ext US_export_policy jar rmiregistry amp java Djava rmi server codebase http mywebserver SNMPEnterprises SNMP examples classes Djava security policy policy RM lServer 5 ensure that the web server can resolve the hostnames of any clients that attach to it either through DNS or a local host file 6 use a browser or the JDK appletviewer to view the applet appletviewer http mywebserver jSNMPEnterprises SNMP examples RmiV1WalkerApplet html Note that Sun also provides a small pure Java HTTP server that can be used in place of the Apache web server Also more discussion on the RMI registry servers and applets can be found at http java sun com j2se 1 3 docs guide rmi getstart doc html 7445 Q When I run your RmiV1WalkerApplet html under Internet Explorer got the following error Couldn t connect to jSNMP RMI Server foo foo com java rmi RemoteException No registry handler present What s up A You need to download the RMI classes for Internet Explorer Download the RMI classes from Microsoft and unzip the rmi zip file into your Windows java directory Any unzip utility capable of handling long filenames can be used such as WinZip Alternately you c
13. ackage with an expiration date longer than 30 days for use in my university course work A We offer free extended licenses under the SNMP Enterprise Educational License Program for educators and their students using jSNMP Enterprise in organized classes independent study projects unfunded research and other not for profit educational activities For further information visit our web site at http www jsnmp com products html educational_ position Q Does jSNMP support all platforms without any modification Our target platforms are Linux Solaris BSD SCO AIX HP UX and Windows NT If not what issues should be taken care A jSNMP Enterprise will run on any OS that has a Java VM that supports basic TCP IP networking Note that jJSNMP Enterprise requires a JDK 1 1 x or later compatible development and runtime environment To support DES encryption in SNMPv3 requests a Java Cryptography Extension JCE must be installed along with a JDK 1 2 1 or later compatible development and runtime environment If the encryption feature of SNMPv3 is not used a JCE is not required The additional RMI interfaces require a JDK 1 2 x or later compatible development and runtime environment or any other Java development and runtime environment with RMI support An RMI environment is not required for local operation Q AdventNet sent me a document with a comparison with your package Do you care to comment on that comparison Do you have your own com
14. an get a nice bundled package from IBM that installs the RMI classes in the right location Copyright 2003 jSNMP Enterprises All Rights Reserved 14 Q When I run your RmiV2TrapListenerApplet under Netscape and add a host it gives me an exception What s up A You are most likely loading the applet from your local file system The problem here is related to security privileges and principals in Netscape In order to successfully request a set of privileges to perform normally forbidden actions in Netscape like opening a listing socket contacting arbitrary hosts etc the applet must be loaded from a trusted principal Normally this is accomplished using signed applets You can also accomplish the same thing using a Netscape workaround called Activating Codebase Principals What this does is tell the browser to treat a codebase named in an HTML file as a trusted principal just as if it were signed You must also use a web server as the source of all classes as explained in the answer to the previous question Note that Netscape recommends against using this approach in a production setting Q When I run my RMI application it gives me the following java net ConnectException Connection refused no further information What s up A You probably aren t running a jSNMP RMI server A jSNMP RMI server must be run with a security policy under the RMI registry server on the same machine Please refer to the User s Guide for mo
15. application already listening on the trap port Also the BindException that you are getting may be a Unix specific issue Only the root user on a Unix platform is allowed to open up a socket with a port number less than 1024 SnmpV1V2V3TrapListenerTest uses the default notification port 162 Either run SnmpV1V2V3TrapListenerTest as root or modify the SnmpV1V2V3TrapListenerTest java file to create the SnmpTrapListener with a port greater than 1023 don t forget to reconfigure your SNMP agent to send traps and informs to the new port Q My jSNMP application seems to be losing traps What s up A Previous versions of SNMP were very susceptible to losing traps and informs during trap or inform bursts jJSNMP Enterprise 3 x is able to handle sustained bursts of 100 400 or more incoming traps informs per second without loss depending on the operating environment This was calculated on a 400MHZ Intel P3 Windows NT machine In fact bursts of over 1000 traps per second were received without loss but not at a sustained rate Note that the trap inform queue capacity and expansion size can be manipulated through SnmpServiceConfiguration class methods This should not be necessary as the defaults though large are optimal Q My jSNMP application receives traps okay but the address of the agent is different from the agent that sent the trap What s up A SNMP traps can be delivered by a different agent that the one that originat
16. d SnmpConstatnts SNMP ERR RESPONSENOTGENERATED for the rest of the varBinds past the end of the MIB Copyright 2003 jSNMP Enterprises All Rights Reserved Q Is it possible to make a getBulkOrder request without non repeaters A Yes by setting the szNonRepeaterOIDs argument of your placeGetBulkOrder call to null Q In what order does jSNMP deliver table rows and columns when making a getBulk request A Most SNMP agents deliver getBulk requests on tables by rows c1 1 61 2 1 3 62 1 c2 2 c2 3 etc When JSNMP receives the packet to the getBulk request it separates out each varBind from the varBindList and delivers them on separate threads to your deliverSuccessfulOrder method Since they are delivered on separate threads there is no guarantee that they will be delivered in order though they usually are Q I am using the SnmpConstants SNMP_VERSION_xxx constants from jSNMP in my code The behavior was not as anticipated so printed the values of the three constants I got the following result SnmpConstants SNMP_VERSION_1 0 SnmpConstants SNMP_VERSION_2 1 SnmpConstants SNMP_VERSION_3 3 Can you explain why the values are not sequential A The versions are defined with these values in the SNMP specifications We decided to use the same values instead of doing extra conversions within our code Q I am facing a problem while retrieving values for the ifDescr obj
17. e As this is not available in CLDC the standard release of jSNMP wouldn t be compatible with that configuration nor any profile based on that configuration am not familiar with CDC so can t advise you on that topic We do sell a source license so you should be able to port jSNMP to whichever configuration or profile you end up with However can t advise you on how much work this would entail Copyright 2003 jSNMP Enterprises All Rights Reserved 2 Q We are interested in using jSNMP in a control monitoring system via a Java Applet One of our concerns is Jar size requirements as the Java Applet needs to be downloaded via HTTP sometimes over a modem What are the size requirements for jSNMP just for basic SNMP communication A The jSNMPEnterprise jar 677KB is the full jSNMP client and server implementation with RMI and Corba support If your Applet is not a jSNMP RMI or Corba client use the jSNMP jar 413KB If it is a jSNMP RMI client you can use the jSNMPRmiClient jar 632KB If it is a jSNMP Corba client you can use the JSNMPCorbaClient jar 458 KB Q I am evaluating jSNMP for use within our product am particularly interested in SNMPv3 support Does jSNMP support discovery and synchronization i e does it allow you to synchronize with an authoritative engine so that requests traps sent to that engine are considered timely A jSNMP Enterprise supports both V3 discovery and synchronization timeliness When
18. ect in interfaces table in MIB II This variable has a type of type OctetString but when I use the getStringValue method on the varBind it gives me a value in hexadecimal numbers For other strings in the system group am able to see the proper text What is causing jSNMP to show the value in hex instead of in printable text Here is what am getting Value for OID 1 3 6 1 2 1 2 2 1 2 16777219 is 0x33 0x43 0x6f 0x6d 0x20 0x45 0x74 0x68 0x65 0x72 0x4c 0x69 0x6e 0x6b 0x20 0x50 0x43 0x49 0x00 Type 4 A What you are seeing is the result of your agent sending null terminated DisplayStrings Note that DisplayStrings are just OctetStrings and can contain any character 0x00 to Oxff The getStringValue method creates a String from the internal representation of the object value here byte If any character is non printable it creates a hex string as you have noticed To get around this first determine the object type with the get Type method and if itis SnmpConstants ASN OCTSTR get the object value with the getValue method which will be of type byte and create your own String from the byte object Copyright 2003 jSNMP Enterprises All Rights Reserved 8 SNMP Traps Q I can run the SnmpV1V2V3TrapListenerTest example just fine on a Windows 95 NT machine but on a UNIX platform I get the following message java net BindException Permission denied What s up A One possibility is that there is another SNMP
19. ed the trap The SnmpTrapEvent getAgentIPAddress method returns the address of the originating agent and the SnmpTrapEvent getSendersIPAddress method returns the address of the sending agent Q Would you please tell me why when sending a large number of traps we are seeing a large number of threads being created A In order to handle traps a quickly as possible SNMP uses a single thread to pull the trap packet off of the stack as the trap comes in and places it in a queue a second thread pulls them off of the queue spawning another thread for decoding and delivery Note that your callback method should return as soon as possible in order for the spawned thread to die Q My jSNMP application is failing to send traps and we get the following message Wed Jul 10 16 46 16 EDT 2002 79 Thread 3 SNMP service unable to send PDU to 68 38 118 247 request too big I guess the PDU is becoming bigger than it can handle We must have too many varBinds 18 Please let me know the maximum size of a PDU or how can provide a workaround for this problem A SNMPv1 2c defines a max PDU size of 484 bytes SNMPv3 determines the PDU size through discovery with the SNMP agent jSNMP uses these as defaults The SNMPv1 2c defaults can be over ridden with the command line configuration parameter jsnmp ignoreV1V2PduSizeLimit which will set the PDU size limit to the socket send receive buffer size usually 8192 depending on the OS Note that
20. essageDigest class Netscape is not available when using authentication and the JCE package Netscape and Internet Explorer is not available when using authentication and or encryption The solution is to install a Java Plug in in the Browser using JRE 1 2 2 or later and a JCE provider for authentication and encryption Q I have a multi get request with different OIDs What happens if the some of the get requests are in the cache and some are not My assumption would be that only the requests that are not in the cache get generated Is this correct or will the whole get request be sent out A The cache is granular as you suspect Each OID is evaluated separately and if it is available in the local cache that OID will not be re requested OIDs that are missing from the cache will be requested For a cache hit to occur the following parameters must match OID host port security info order info That is in order for a value to be available for a cache hit it must have been requested with all of the above parameters equivalent to the new request s parameters Copyright 2003 jSNMP Enterprises All Rights Reserved 4 Q What is the difference between setting the CacheThreshhold argument to 0 in the SnmpOrderlInfo class and making atomic requests by setting the bAtomic argument to true in the SnmpService placeXXXOrder methods A Setting LCacheThreshhold to 0 in the SnmpOrderInfo class means that the order will not be retri
21. eved from the cache though its result will be put in the cache It also means that the order MAY not be atomic that is the order MAY be split into multiple PDUs or combined into other PDUs Atomic requests WILL not be retrieved from the cache WILL not be put in the cache and WILL be sent in one PDU Q I have a question about the responses to placeSetOrder request In SNMP a SET request is atomic Why must I specify it in the placeSetOrder call A The bAtomic argument to the placeSetOrder method if true informs the jSNMP engine that you wish to send all of the OID SET requests in the same PDU You should specify true in most cases as it matches the SNMP specification for SETs Setting this argument to false allows jSNMP to split up your SET request into multiple PDUs if it desires This allows you to specify more OIDs in your placeSetOrder than could possibly fit in a single PDU Q I see that you now have an option that disables the cache Why would want to disable it A The cache in jSNMP Enterprise is optimized for servicing large numbers of jSNMP clients It does improve latency and reduce network traffic when cache hits occur However some customers have reported that under continuous heavy load the memory used by the cache can become quite large multiple megabytes It has also been noted that not all SNMP management systems benefit from a cache i e cache hits are specifically avoided Setting the system proper
22. fer to the M Bs section of the SNMP Enterprise User s Guide jSNMP Enterprises also provides jMIBC a Java based MIB Compiler which produces SnmpMIBService compatible dictionary files i e jmib files from MIBs Q Is there any way to generate an SNMP trap with jSNMP A You can send traps and informs via the placeTrapOrder and placeInformOrder methods of the SnmpService interface The SnmpV1TrapSenderTest java file in the examples illustrates how to send traps Q Is it possible to use jSNMP with Servlets A jSNMP is a pure Java implementation Many customers have created Servlets with jSNMP Q I am developing a product using jSNMP and would like to send out a broadcast on the local subnet and get responses back from all agents on the subnet Is this possible A There is no interface within jSNMP to broadcast SNMP requests Q I want to use SNMPv3 encryption What do I need to do A jSNMP supports encryption in SNMPv3 requests To support encryption a Java Cryptography Extension JCE must be installed JCE providers other than Sun s are available Note that the JCE requires a JDK JRE or version 1 2 1 or later If the encryption feature of SNMPv3 is not used a JCE is not required Q I want to run a jSNMP SNMPv3 applet in a browser What do need to do A jSNMP applets that make SNMPv3 requests using authentication and or encryption may fail by throwing a java lang NoClassDefFoundError exception as the M
23. fixup read permission java util PropertyPermission browser read or add the following single permission permission java security AllPermission Alternately you can use a policy file supplied on the command line For instance appletviewer J Djava security policy policy all yourSnmpApplet Q I am using Microsoft Visual J 1 1 and am having trouble compiling the sample applications Does your product work with the Microsoft tool A Either upgrade to Microsoft Visual J Version 6 0 or see the Microsoft Knowledge Base Article INFO Use New Java 1 1 Language Features with Visual J 1 1 Using jMIBC Q Would you please help me with the installation of jMIBC A You should have received a jMIBC jar file in the distribution The jMIBC jar file can be installed anywhere ona system The user s manual will be in the doc directory and will help you getting started Copyright 2003 jSNMP Enterprises All Rights Reserved 11 Q I am using JDK 1 1 how do compile a MIB A If you are using JDK 1 1 you will need to set the CLASSPATH environment variable to run jMIBC For example this could be accomplished with the following command set CLASSPATH C jSNMP jMIBC jar CLASSPATH for Win32 systems or export CLASSPATH jSNMP jMIBC jar SCLASSPATH for Unix systems Running jMIBC can be accomplished with the following command java jJMIBC options lt mibfile gt Q I am using JDK 1 2 how do I compile a MIB A
24. hat 1 3 6 1 4 1 8845 1 2 1 2 1 1 1 17825798 is the last OID in your MIB or the last OID you have permission to access in your MIB An order fails when it can t do the GETNEXT The text General Error can be agent specific Sometimes it will return No Such Name in the same situation Q Is jSNMP thread safe My problem is the iOrderNumber Is one iOrderNumber shared by every SnmpCustomer big problem or do have one iOrderNumber per SnmpCustomer Is the iOrderNunber sent by callback to all SnmpCustomers or is it sent to only one SnmpCustomer A jSNMP Enterprise is thread safe Orders and their corresponding iO0rderNumbers are not shared between SnmpCustomers All orders pb lacexxxXOrder placed by a SnmpCustomer are returned to its deliverSuccessfulOrder or deliverFailedOrder methods only Q I currently create a SnmpAuthoritativeSession for each combination of host port context user authentication password privacy password authentication scheme privacy scheme and security level Is that the way to do it Does that mean that on every change for one of those parameters should create a new session Isn t the creation of a session a heavy operation does it creates a new thread does it do a large memory allocation A If you require SNMPv3 authentication and privacy you are creating the session correctly It does not create a new thread nor does it allocate large amounts of memory Since you are creating a SN
25. ictionary file that is used by the SNMP Enterprise SnmpMIBService to translate OIDs to from common names to retrieve an OID s status access type abstract type and description and to translate OID enumerated values Note that beginning with jSNMP Enterprise 3 2 it is no longer necessary to precompile MIBs to dictionary files with jMIBC as MIBs can be loaded at runtime with the new jMIBC loadMib method Q What is jSNMP Enterprises support policy A TECHNICAL SUPPORT is provided free of additional charge via electronic mail Technical questions along with any error codes exceptions source code system configuration JDK and JVM version numbers etc should be sent directly to support jSNMP com The more relevant information you can provide the better we can support you Copyright 2003 jSNMP Enterprises All Rights Reserved 1 Q What is jSNMP Enterprise Update and Upgrade policy A UPDATES are defined as Product Maintenance Releases which include but are not limited to bug fixes and incompatibility resolutions These releases are included with the jSNMP license at no additional charge UPGRADES are defined as Major Product Releases which include but are not limited to feature enhancement and or additions These releases are not included in the original license fees Upgrade pricing policies will be set at the time of the Upgrade release Q Is it possible to obtain an evaluation copy of the jSNMP p
26. it after making each request Q If create a SnmpOrderlnfo object with a timeout of 5 seconds 2 retries and a cache threshold of 1000 milliseconds how many times is the deliver failed order called before the manager stops sending requests As an example my placeGetBulkOrder method is placed with 4 OIDs and 10 maximum repetitions My deliverFailedOrder method simply prints a message indicating a failure has occurred What I am currently observing is that the deliverFailedOrder is called indefinitely My expectation is that the calls would be stopped after 2 retries Is my assumption incorrect A You will receive either 1 deliveredSuccessfulOrder or1 deliverFailedOrder call for each OID or potential OID i e placeGetBulkOrder in a request A deliverFailedOrder will be called once the number of retries has been exhausted It will not happen indefinitely Note that with a placeGetBulkOrder placed with 4 OIDs and 10 maximum repetitions you could receive 40 deliveredSuccessfulOrder deliverFailedOrder calls as you have 40 potential OIDs Q I am sending a placeGetBulkOrder request with 4 repeater OIDs in the request In my deliverSuccessfulOrder implementation am able to detect when I reach the end of the table However continue to receive orders for what seems to be an indefinite amount of time The MIB on our device has the potential of being very large Once that have detected the end
27. jSNMP Enterprise 3 2 FAQ Basic Information Q What is SNMP A SNMP is the acronym for Simple Network Management Protocol SNMP is an Internet Standard Protocol designed to give a user the capability of remotely managing devices from different vendors by polling and setting values and monitoring network events SNMP network management consists of two major components a Manager such as a jSNMP application or HP OpenView and an Agent running in each of the devices you wish to manage For more information see SNMP amp CMIP An Introduction to Network Management Q What is the jSNMP Package A jSNMP is a highly optimized and scalable Java package for communicating with SNMP devices and services It is written entirely in Java and is completely portable jSNMP provides complete SNMPv1 SNMPv2c and SNMPv3 support including notification handling Q What differentiates jSNMP from other SNMP packages A Since jSNMP is 100 pure Java it has the advantage over non Java SNMP packages in that it will run on any Java 1 1 or later compatible Virtual Machine To support SNMPv3 encryption a Java Cryptography Extension JCE must be installed along with a Java 1 2 1 or later Virtual Machine Additionally jSNMP presents a set of simple interfaces to developers without requiring them to know the finer details of SNMP These same interfaces can be accessed from across the network via a RMI or CORBA 2 0 Client In addition JSNMP Enterprise
28. parison that describes YOUR advantages The following points of comparison are of special interest for us MIB browser inclusion storing SNMPv3 parameters in a database and support through the HTTP protocol A We are reluctant to get in feature by feature comparison debate with AdventNet s marketing blurb We do not include a MIB browser store SNMPv3 parameters in a database this is something you can easily do yourself nor support SNMP via HTTP jSNMP Enterprise does support communication via RMI and CORBA and we would recommend the use of RMI for any remote Java support Note that it does not mention any lack of SNMP support but a lack of utilities that you may or may not require Note that we purposely have not included a myriad of features MIB browser database support etc to jSNMP Enterprise in order to keep the price as low as possible We suggest if any of the features of AdventNet s product are must haves and you are willing to pay their price initial cost plus redistribution costs that you choose their product If you require solid SNMPv1 2 3 support in Java at a reasonable price 995 00 USD per developer which includes a royalty free runtime redistribution we think jSNMP Enterprise will be suitable for your needs Q Is jSNMP J2ME compliant We would like to use it on a PDA so it should be able to run any profile configuration you need We re looking at CDC Personal and CLDC PDA A jSNMP uses the J2SE java net packag
29. pyright 2003 jSNMP Enterprises All Rights Reserved 13 ISNMP and RMI Q What is RMI A RMI Remote Method Invocation is a distributed object architecture that allows programmers to develop distributed Java programs with the same syntax and semantics used for non distributed programs For more information see Sun s Java Remote Method Invocation Q How do I enable my application to access the remote RMI jSNMP services A First create an RMISnmpClient object Next replace all method calls that use the previously created SnmpLocalinterfaces object with the equivalent RMISnmpClient method calls That s all there is too it Q What is the best way to provide classes under RMI A You should use a web server as the source of all classes The following instructions illustrate running a JSNMP RMI Server under Red Hat Linux 6 2 using the Apache web server and the Java 2 SDK 1 3 1 create the SNMPEnterprises SNMP examples classes directory under the document root home httpd html place all jSNMP classes and jars into the SNMPEnterprises SNMP examples classes directory place all of your HTML files i e RmiV1WalkerApplet html referencing the jSNMP classes in the JSNMPEnterprises SNMP examples directory 4 in a console window set the CLASSPATH to the SNMPEnterprises SNMP examples classes directory and start the RMI registry and jSNMP RMI server specifying the RMI codebase cd home httpd htmI SNMPEnterprises S
30. r 2000 compliant A Yes jSNMP has been examined and determined to be Year 2000 compliant jSNMP depends on a third party environment e g operating systems Java virtual machines SNMP agents etc in order to operate Although jSNMP Enterprises is not aware of any Year 2000 issues with these third party components it cannot guarantee their Year 2000 compliance and does not assume any responsibility for their non compliance Copyright 2003 jSNMP Enterprises All Rights Reserved 16
31. re information ISNMP and CORBA Q What is CORBA A CORBA Common Object Request Broker Architecture is a distributed object architecture that allows software objects to interact across networks CORBA objects can interact regardless of implementation language location or host platform CORBA was first introduced in 1991 by the Object Management Group OMG a consortium of over 800 software vendors software developers and end users CORBA addresses the need for interoperability among the rapidly proliferating number of hardware and software products available today Q placeGetOrder doesn t seem to be supported with the CORBA jSNMP services A That is correct Only those interfaces present in SNMP 2 0 are supported in the CORBA interfaces None of the new interfaces or SNMPv2c and SNMPv3 are supported with the CORBA interfaces If you require these new interfaces SNMPv2c or SNMPv3 in a distributed environment the RMI interfaces in SNMP 3 x are available Alternatively the RMI interfaces in jSNMP 3 x may be used with RMI over IIOP Q How do I enable my application to access the remote CORBA jSNMP services A Compile the IDL to generate the stubs particular to your language and environment The generated stubs then provide a local interface to the remote CORBA jSNMP service Because the jSNMP service is exposed through CORBA IDL a developer can access distributed jSNMP services in any language that supports a CORBA 2 0
32. s so that you don t need to be a CORBA expert to use JSNMP Enterprise You should be familiar with CORBA though and be able to compile the IDL that comes with jSNMP Enterprise to generate the CORBA stubs However unless you are implementing a client in a language other than Java you don t need to communicate through these CORBA interfaces jSNMP Enterprise does this for you The only other step required of the developer is to communicate the object references of the server components to the client This may be done through a naming service or through a file system The task is discussed in more detail in the user s manual Q What else do need to use CORBA with jSNMP Enterprise A You will need a CORBA 2 0 ORB development environment compatible with the standard CORBA to Java mapping ORB vendors providing environments include lona Visigenic and Javasoft Sun s JDK 1 3 includes a CORBA ORB that is compatible with jSNMP Miscellaneous Q How does jSNMP Enterprise relate to Sun s JMX and JDMK A jSNMP Enterprise is a toolkit for building SNMP manager applications Sun s Java Management Extensions JMX and Java Dynamic Management Kit JDMK are focused on building Java based management agents that can communicate with managers using a variety of protocols RMI HTTP etc The JMX and JDMK do include an SNMP Manager API with limited functionality but it is not the primary focus of the package Q Are jSNMP and jMIBC Yea
33. the number of OIDs that will be packed into a single non atomic request PDU Use the command line option Djsnmp maxClerk 24 Q If place a getBulk request with maxRepititions gt 25 does the maximum number of SnmpClerks get changed to the larger value If place a getBulk request with maxRepititions 25 against a table containing 75 entries then are the SnmpClerks from the original SnmpInvoice reused for subsequent getBulk requests or are separate Snmplnvoices and or SnmpClerks created A With placeGetBulkOrder requests the number of clerks is ignored The SnmpInvoice will create as many clerks as necessary Copyright 2003 jSNMP Enterprises All Rights Reserved 6 Q An SNMP agent that I used to be able to access is no longer accessible think you have a trace capability within jSNMP Would you tell me how I can trace using this A From the command line run java Doutback trace trace Djsnmp dumpPackets true your_application Q I ve just run the SnmpV2Walker java example against one of our devices and it worked pretty darn well until the following 10819 1 3 6 1 4 1 8845 1 2 1 2 1 1 1 17825796 channel 4 10820 1 3 6 1 4 1 8845 1 2 1 2 1 1 1 17825797 channel 5 10821 1 3 6 1 4 1 8845 1 2 1 2 1 1 1 17825798 channel 6 10822 order failed General Error Ending MIB Walk Can you help me understand what the error means and what could cause it A This appears to be a normal termination and suspect t
34. the socket send receive buffer size can also be over ridden with the command line configuration parameter jsnmp socketBufferSize or through the SnmpServiceConfiguration setSocketBufferSize method Copyright 2003 jSNMP Enterprises All Rights Reserved 9 Q I use jSNMP to generate a coldStart alarm on one machine and send it to another machine where the details of the alarm are printed out However when I generate the alarm am specifying its trap type as 1 but on the receivers end it says the trap type is 0 was wondering if you could explain what am doing wrong A You are doing nothing wrong What you are seeing is one of the vagaries in the translation of SNMPv1 and SNMPv2 traps In jSNMP the SnmpTrapEvent Class is based upon the SNMPv2 trap specification http www ietf org rfc rfc1905 txt RFC 1905 Protocol Operations for Version 2 of the Simple Network Management Protocol That is all traps are specified by an enterprise OID and trap code The generic SNMPv1 traps co dStart warmStart linkDown linkUp authenticationFailure and egoNeighborLoss are converted to traps with an enterprise OID of 1 3 6 1 6 3 1 1 5 and corresponding trap codes of 1 2 3 4 5 and 6 see http www ietf org rfc rfic2576 txt RFC 2576 Coexistence between Version 1 Version 2 and Version 3 of the Internet standard Network Management Framework When you send your coldStart trap with java SnmpV1TrapSenderTest 10 24 39 237 public 1 3 6 1 6
35. ty jsnmp cacheDisable true will conserve both memory and CPU This option is recommended if the cache is not perceived as providing specific benefit or if resource problems occur under heavy load Q We are working on internationalizing our product and a question came up in regards to jSNMP Is there a way to retrieve the character encoding that the SNMP Agent is talking in noticed that JjSNMP return Strings represented in ASCII bytes from SnmpVarBind Am correct in assuming that the byte values are unaltered before this point If the SNMP Agent sends bytes in Shift_JIS are they delivered in SnmpVarBind as is A jSNMP does not have the ability to determine what character set the remote agent is using It does translate different character sets correctly if the file encoding parameter is set correctly For more information about encodings see Sun s tutorial on internationalization Q We have a problem with an IP address that uses DHCP am using the DNS name to access SNMP The provider switches IP addresses every day What happens is that the old address is remembered by jSNMP until Tomcat is rebooted Do you have any suggestions for this problem A When created jSNMP s SnmpAuthoritativeSession simply calls InetAddress getByName on the hostname and stores the result InetAddress getByName is only called once during the lifetime of the SnmpAuthoritativeSession in order to improve performance The InetAddress class has a
36. undefined Please define using the b option or include all dependent MIB files A This message will be displayed if a reference to an OID name is encountered that has not been found in the file The recommended way to correct his problem is to include all the dependent MIB files using the i option in the correct order The dependent MIB files can be determined by looking at the IMPORT definitions and including all the MIB files referenced in the FROM clause Copyright 2003 jSNMP Enterprises All Rights Reserved 12 Q Why did get the following warning Warning Redefinition of lt name gt in lt file gt Previously found in lt file gt A This warning indicates that a type identifier or OID has been redefined The last definition found will be used This warning will only occur if the definitions differ The recommended way to handle this is to either remove the redefinition or make the definitions identical Q Why did get the following error Error Parsing file lt file gt A This message indicates that there was an error parsing the input file The file name where the error is detected is printed on the error line Additional details of the error will follow and typically include the line number and column where the error was encountered The following error message indicates that an enumeration begins with a digit Error Parsing file lt file gt Encountered 1 at line 8036 column 25 Was e
37. xpecting one of lt LCASEFIRST_IDENT_TKN gt lt UCASEFIRST_IDENT_TKN gt The following example illustrates an error where the RFC file was not edited to remove the extraneous text Error Parsing file lt file gt Encountered Working at line 1 column 9 Was expecting one of TTA DEFINITIONS EORCE INCLUDE EXCLUDE Q How does the CERT Advisory CA 2002 03 apply to jJSNMP Enterprise A jSNMP Enterprises acknowledges the potential of SNMP vulnerabilities as identified in the following CERT advisories 1 VU 854306 Multiple vulnerabilities in SNMPv1 request handling 2 VU 107186 Multiple vulnerabilities in SNMPv1 trap handling jJSNMP Enterprises has investigated how these vulnerabilities may impact the jSNMP Enterprise product and has determined the following 1 VU 854306 This advisory is not applicable to jSNMP as jSNMP does not accept or process SNMP Get Set or GetNext PDUs rather SNMP sends those requests to SNMP agents and processes subsequent responses 2 VU 107186 jSNMP v3 2 passed the 24 098 applicable tests in the PROTOS c06 snmpv_1 test suite JSNMP v3 1 failed only one test with undesirable behavior No consequences other than potential denial of service are known and there have been no reported instances of this vulnerability being exploited in the JSNMP product We recommend that our customers upgrade to the latest available version of SNMP Co
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