Template:FAQ:MIBs 03

There are two basic likely causes - either the library isn't attemping to load these particular MIB files, or it's trying to load them but can't locate them.

By default, the Net-SNMP library loads a specific subset of MIB files. This list is set when the suite is first configured and compiled, and basically corresponds to the list of modules that the agent supports.
(This is a simplification, but is a reasonable first approximation).

In order to load additional MIB files, it is necessary to add them to this default list. See the FAQ entry "How do I add a MIB to the tools?" for more information about how to do this.

Alternatively, the tools may be looking in the wrong place. The directory where the library looks for MIB files is also set when the software is first configured and compiled. If you put new MIB files in the wrong location, then the library won't be able to find them (and will complain).

This problem may arise when switching from a vendor-supplied distribution to one compiled from source (or vice versa).
See the next entry for more information.