SNMP Foundations and Concepts8-12 Express5800/ftServer: System Administrator’s Guide for the Linux Operating SystemN O T EThe Express Builder installation automatically creates theSRA-ftLinux-MIB file in the /opt/ft/mibs directory,while Net-SNMP creates its MIBs in the/usr/share/snmp/mibs directory.MIBs can be stored in a variety of locations, but running SNMP agents must still bedirected to the location of a MIB the first time it is to be used, if the MIB is added afterthe agents have already started. If the MIB was not in the path when the SNMPservices were started (and SRA-ftLinux-MIB exported), the following example showshow to identify the SRA-ftLinux-MIB file to the SNMP tools:# snmpget -m SRA-ftLinux-MIB -v 2c -c public myhost.comftcBdState.1SRA-ftLinux-MIB::ftcBdState.1 = INTEGER: duplex(21)As you begin to develop your own MIB (or MIBs) for your management requirements,you can save a lot of work by adopting defined variables from other MIBs. A largenumber of MIBs are defined by the IETF and are available as plain text files. You shoulduse standardized MIBs where they define objects to avoid non-standardimplementation of networked objects.Do not alter standard MIBs. If you need additional object definitions, you can addanother MIB or create your own. The MIB-defined objects can be queried and datarecovered that provides a basis for SNMP agent operations. You can create scripts thatthe SNMP agent or a subagent executes according to MIB definitions.Some Objects Defined by Standard MIBsFor a practical implementation of SNMP, a number of objects simply must be defined.Some of these are introduced here.
