From Net-SNMP Wiki

How do I add a MIB to the tools?

Adding a MIB to the client-side tools has two main effects:

• it allows you to refer to MIB objects by name
  (rather than having to use the numeric OIDs)
• it allows the results to be displayed in a more immediately meaningful fashion. Not just giving the object names, but also showing named enumeration values, and interpreting table indexes properly (particularly for string and OID index values).

Most of the tools (apart from 'snmptable') will work quite happily without any MIB files at all - although the results won't be displayed in quite the same way.

The same holds true for the agent - see the next section for details.

There are two steps required to add a new MIB file to the tools. Firstly, copy the MIB file into the appropiate location:

       cp MY-MIB.txt /usr/local/share/snmp/mibs

(which makes it available to everyone on the system)
or

       mkdir $HOME/.snmp
       mkdir $HOME/.snmp/mibs
       cp MY-MIB.txt $HOME/.snmp/mibs

(which makes it available to you only)

Note that the location of the shared MIB directory may be different from that given here - particularly if you're working with a vendor supplied distribution. See where the MIBs are currently installed, and copy the new MIB to the same place.

Secondly, tell the tools to load this MIB:

       export MIBS=+MY-MIB

(load it for this session only)
or

       echo "mibs +MY-MIB" >> $HOME/.snmp/snmp.conf

(load it every time)

This will add the new MIB to the list of MIBs loaded by default. Omitting the '+' will replace the list of MIBs to be loaded by the specified (colon-separated) list - together with any MIBs that they explicitly rely on.

Note that the value for this variable is the name of the MIB module, not the name of the MIB file. These are typically the same (apart from the .txt suffix), but if in doubt, check the contents of the file. The value to use is the token immediately before the word DEFINITIONS at the start of the file.

If you prefer to have the tools load all available MIBs (which may slow them down), then set the MIBS environmental variable (or the snmp.conf token mibs) to the special value "ALL".

Note that you need both steps.

   FAQ:Applications
   

1. How do I add a MIB?
2. How do I add a MIB to the tools?
3. Why can't I see anything from the agent?
4. Why doesn't the agent respond?
5. I can see the system group, but nothing else. Why?
6. Why can't I see values in the <ENTERPRISE> tree?
7. The agent worked for a while, then stopped responding. Why?
8. Requesting an object fails with "Unknown Object Identifier" Why?
9. Why do I get "noSuchName" when asking for "sysUpTime" (or similar)?
10. Why do I sometimes get "End of MIB" when walking a tree, and sometimes not?
11. How do I use SNMPv3?
12. Why can't I set any variables in the MIB?
13. Variables seem to disappear when I try to set them. Why?
14. Why can't I change sysLocation (or sysContact)?
15. I get an error when trying to set a negative value - why?
16. I get an error when trying to get a string-indexed table value - why?
17. What quotes should I use for string index values?
18. How do I send traps and notifications?
19. How do I handle traps and notifications?
20. My traphandler script doesn't work when run like this - why not?
21. How big can an SNMP request (or reply) be?
22. How can I monitor my systems (disk, memory, etc)?
23. Applications complain about entries in your example 'snmp.conf' file. Why?
24. OK, what should I put in snmp.conf?
25. How do I specify IPv6 addresses in tools command line arguments?