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# WebLogic Server SNMP Agent Contents Overview Using the WebLogic Server SNMP Agent The WebLogic Server MIB SNMP Command Line Applications Traps Additional Resources # Overview The Simple Network Management Protocol (SNMP) was designed to be an easily implemented, basic network management tool that could be used to meet network management needs. SNMP has become the dominant standardized network management scheme in use today. The SNMP set of standards provides a framework for the definition of management information along with a protocol for the exchange of that information. The SNMP model assumes the existence of managers and agents. A manager is a software module responsible for managing part or all of the configuration on behalf of network management applications and users. An agent is a software module in a managed device responsible for maintaining local management information and delivering that information to a manager via SNMP. A management information exchange can be initiated by the manager (via polling) or by the agent (via a trap). Agents function as collection devices that gather and send data about the managed resource in response to a request from a manager. UDP ports 161 and 162 are the default ports reserved for SNMP. The agent listens for requests and replies to them over port 161 and reports asynchronous traps on port 162, unless it is instructed to use different ports. SNMP accommodates resources that do not implement the SNMP software by means of proxies. A proxy is an SNMP agent that maintains information on behalf of one or more non-SNMP devices. SNMP defines a client/server relationship. The network manager makes virtual connections to the SNMP agent which executes on a remote network device, and sends information to the manager regarding the device's status. In order for a manager to make requests of an agent and to interpret the responses and unsolicited traps that it receives, it uses a database which describes the information available from the agent. The database is referred to as the SNMP Management Information Base (MIB). There is a standard set of statistical and control values defined for hardware nodes on a network. These are described in a MIB which is part of the SNMP. SNMP also allows the extension of these standard values with values specific to a particular agent through the use of private MIBs. Directives issued to an SNMP agent consist of the identifiers of SNMP variables (referred to as MIB object identifiers or MIB variables) along with instructions to either get the value corresponding to the identifier, or set the identifier to a new value. Through the use of private MIB variables, SNMP agents can be tailored for use in many devices. The definitions of MIB variables supported by a particular agent are incorporated in descriptor files, and made available to network management client programs so that they can become aware of MIB variables and their usage. These descriptor files are written using a subset of Abstract Syntax Notation (ASN.1) format as adopted by SNMP. When a new agent is added to extend the domain of a manager, the manager must be provided with a new MIB (ASN.1 file) that describes the features of the resources managed through that agent. For information about the WebLogic Server SNMP Agent MIB, please see The WebLogic Server MIB. Why provide an SNMP link to SNMP-compliant management systems? The main reason is that WebLogic Server is part of an overall organization or business solution. It is not the only application that will be running on your network. Integrating WebLogic Server with SNMP allows you to effectively manage all of your large-scale applications using the SNMP-compliant network management tool of your choice. Since most of the management platforms support SNMP today, the WebLogic Server SNMP Agent can be integrated into virtually every management framework. Examples of such systems include: HP OpenView IBM Tivoli, NetView Sun Domain/SunNet/Site Manager CA Unicenter SNMP manageability of WebLogic Server provides the following benefits: Enables you to move towards a single management console and thus provide integrated systems management of WebLogic Server based applications. Enables you to connect WebLogic Server to popular management systems such as HP OpenView, Sun SunNet Manager, and IBM NetView. This makes managing WebLogic Server more effective by providing a whole-system perspective instead of piecemeal solutions. Enables you to preserve your standard-based, compliant (SNMP-capable) management frameworks. Enables you to benefit from the experience of the large community of SNMP users. Enables providers of management applications to customize them for WebLogic Server customers. The WebLogic Server agent will enable you to remotely monitor the status of your server or server cluster. It will report statistics including the availability of your server, the number of connections, and the average queue length. For more information on SNMP and SNMP agents, BEA Manager 2.0, found at the BEA Documentation website # Using the WebLogic Server SNMP Agent To run the WebLogic Server SNMP Agent, you must add the following to your java classpath:
      \weblogic\lib\weblogicaux.jar
      \weblogic\classes
This distribution of the WebLogic Server SNMP Agent includes two startup scripts, startSNMPAgent.cmd and startSNMPAgent.sh. They can be found in the top level of your installation (default = /weblogic). Before you can use either of these scripts, you must read and edit them as indicated in the comments to supply the proper system password and the proper URL for your servers, the proper trap destination for your SNMP manager and other SNMPAgent startup arguments as desired. If you do not want the system password present as clear text in the startup scripts, you may omit the -password parameter and enter it at the keyboard prompt. To run the agent from the command line, enter:
      java weblogic.SNMPAgent
          -password foo
          -serverURLs t3://dns_host_name:7001
Arguments: -user <systemUserId> Id of the system user on all servers to which the agent will be connected. Default = "system" -password <password> The password for the system user (specified in -user) on all systems to which the agent will be connected. For this release, they must all be the same. Mandatory -serverURLs <serverList> Comma separated list of urls of servers and or clusters the agent is to monitor. A single cluster url is needed for all servers in a cluster. For example, if there is a stand-alone server on "hostA" and the "t3" protocol should be used to communicate with it, and a cluster on the dns name "cluster" on port 7001, with the "admin" protocol in use on port 8001, -serverURLs t3://hostA:7001,admin://cluster:8001 Mandatory -snmpPort <snmpPort> The port on which the agent will listen for SNMP requests. Default = 161 -trapDestinations <trapList> Comma separated list of host:port on which the agent will send SNMP traps. Default = localhost:162 -help Display usage message. -refreshInterval <sec> Interval, in seconds, at which to check the server status. This is the minimum amount of time all MIB values are cached before the agent attempts to re-fetch them from the server. If new values can not be fetched from the server the last known values are returned. Default = 300. -community <snmp-community> String that allows you to set the snmp community which is used by the agent to authenticate incoming snmp requests. Default = "public". -otherAgents <otherAgents> If you need to run other SNMP agents with the WebLogic Server SNMP Agent on the same machine you may have several choices. If another agent has a master agent capability, you can integrate the WebLogic Server Agent with it according to the instructions in the master agent's documentation. If no other agent has master agent capacity, the WebLogic Server Agent can coordinate SNMP requests with the other agents specified in this option. Comma separated list of urls of agent specifiers for which the WebLogic Server agent will act as a proxy. Each agent specifier consists of the following parameters: portNum Specifies the port number on which the agent will be running. Mandatory supportedOIDRoot Specifies the object identifier for the root of the MIBs supported by the agent. Mandatory community Specifies the SNMP community to be passed on for all requests to the agent. Optional By default this is the same as the community contained in the incoming SNMP request. timeoutMilliseconds Specifies the timeout value for any requests sent to the agent. Optional Default=5000 For example: -otherAgents 7000:1.3.6.1.2.1:xyz:2000 which specifies an agent running on port 7000, supports mib-2, and has a timeout value of 2000 ms. ### Note: If you intend to run the WebLogic Server SNMP Agent as the only agent on the system you may not be able to start it if any other agent is already running and it is bound to the snmp port (161). # SNMP Command Line Applications The WebLogic Server SNMP Agent distribution includes several basic SNMP command line applications which will allow you to execute individual SNMP requests. snmpget This application allows you to manually get information about one or more specific objects from the agent using the SNMP GET request. snmpgetnext This application allows you to manually get information from the agent using the SNMP GETNEXT request. snmptrapd This application allows you to test receiving traps from the agent. snmpv1trap This application allows you to generate a trap. It may be used to see if the manager receives the information. snmpwalk This application uses a series of getnext commands to recursively traverse a MIB supported by an SNMP agent. For more information about the command line applications see: AdventNet Agent Toolkit - Low Level SNMP API Examples # Traps The WebLogic Server SNMP Agent has the ability to issue unsolicited reports to a manager when it detects certain events on the server. In SNMP terminology, these unsolicited event reports are called trap notifications. All of the traps generated by the WebLogic Server SNMP Agent are enterprise-specific traps (trap type = 6). The trap subtype may be one of the values indicated in the BEA_WEBLOGIC_MIB.asn1 file: 5 Server restart 10 Server available 15 Server unavailable 20 Server shut down # Additional Resources: BEA Manager 2.0 Documentation

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