Configuring the Simple Network Management Protocol (SNMP)

The definitions file

For objects that are not known to the SNMP library routines (for example, objects belonging to a vendor-specific or a third-party MIB), the commands getmany, getnext, getone, and setany will only identify these objects by their OID in numeric dot-notation format. This means you cannot pass to these commands a text name for such objects (they will not recognize the text name), and when the command displays information, it will display the object using a numeric dot-notation OID.

Using the numeric dot-notation format to identify an object is cumbersome compared to using the text name format. For example, it is easier to talk of ``ifAdminStatus'' than to talk of ``1.3.6.1.2.1.2.2.1.7''. (The object ``ifAdminStatus'' is used here only to compare the two OID formats: text and numeric dot-notation. These commands do recognize the text name ``ifAdminStatus''.)

This limitation is overcome by passing to these commands a definitions file that maps the OID in numeric dot-notation format into the text name. This definitions file is passed on the command line using the optional argument -f. The syntax of these commands is

<SNMP command> [-f defns_file] node community other_arguments ...

The definitions file passed to these commands must be a processed version of the file containing the vendor-specific or third-party MIB module. For information on creating a MIB module, see ``MIB modules''. This MIB module must be processed by two commands to create a definitions file in a format that the commands getmany, getnext, getone, and setany can read. Use the commands mosy and post_mosy, in this order, to process the MIB module. See mosy(ADMN) and post_mosy(ADMN) for the command syntax and descriptions.