Essential SNMP, 2nd Edition

OpenView's Extensible Agent

Before you start playing around with OpenView's extensible agent , make sure that you have its master agent (snmpdm) configured and running properly. You must also obtain an enterprise number, because extending the OpenView agent requires writing your own MIB definitions, and the objects you define must be part of the enterprises subtree.^[*] Chapter 2 describes how to obtain an enterprise number.

MIBs are written using the SMI, of which there are two versions: SMIv1, defined in RFCs 1155 and 1212; and SMIv2, defined in RFCs 2578, 2579, and 2580. RFC 1155 notes that "ASN.1 constructs are used to define the structure, although the full generality of ASN.1 is not permitted." While OpenView's extensible agent file, snmpd.extend, uses ASN.1 to define objects, it requires some additional entries to create a usable object. snmpd.extend also does not support some of the SNMPv2 SMI constructs. In this chapter, we will discuss only those constructs that are supported.

By default, the configuration file for the extensible agent in the Unix version of OpenView is /etc/SnmpAgent.d/snmp.extend. To jump right in, copy the sample file to this location and then restart the agent:

    $ cp /opt/OV/prg_samples/eagent/snmpd.extend /etc/SnmpAgent.d/
    $ /etc/rc2.d/S98SnmpExtAgt stop
    $ /etc/rc2.d/S98SnmpExtAgt start

You should see no errors and you should get an exit code of 0 (zero). If errors occur, check the snmpd.log file.^[†] If the agent starts successfully, try walking one ...