FAQ:Agent 04

How do I remove a MIB from the agent?

Deleting the text file for a MIB does not affect the agent (other than to prevent it from recognising MIB object names in the config files). It's necessary to tell the agent not to activate the relevant code that actually implements these objects. There are three ways to do this:

There are three options to prevent the agent returning information from a particular MIB:

• re-run configure to exclude the given MIB module(s) from the build configuration, then recompile and reinstall:

         ./configure --with-out-mib-modules=path/to/unwanted   ....
         make
         make install

This specifies the path to the module code file, relative to the agent/mibgroup directory. Clearly, this approach is only possible if you are working with a source distribution.

• disable the MIB at runtime

         snmpd -I -unwanted

Note that this relies on knowing which modules are used to implement the relevant MIB objects. If you're not sure, you could try walking the nsModuleName MIB object, which indicates the module responsible for each particular range of OIDs.

You can also check which MIB modules are loaded by getting the agent to report them as they are initialised:

         snmpd -Dmib_init -H

From this information, it should then be fairly obvious which modules to disable.

• use access control to exclude the mib from the view used to query the agent:

         view    almostEverything  included   .1
         view    almostEverything  excluded   unwantedMib
         
         rocommunity  public  default  -V almostEverything

This approach can also be used with the full com2sec/group/access configuration directives (e.g. with versions earlier than 5.3, which don't support the above mechanism).

   FAQ:Agent
   

1. What MIBs are supported?
2. What protocols are supported?
3. How do I configure the agent?
4. How do I remove a MIB from the agent?
5. I've installed a new MIB file. Why can't I query it?
6. How do I add a MIB to the agent?
7. What's the difference between 'exec', 'sh', 'extend' and 'pass'?
8. What's the difference between AgentX, SMUX and proxied SNMP?
9. What is the purpose of 'dlmod'?
10. Which extension mechanism should I use?
11. Can I use AgentX when running under Windows?
12. How can I run AgentX with a different socket address?
13. How can I turn off SMUX support?
14. How can I combine two copies of the 'mib2' tree from separate subagents?
15. What traps are sent by the agent?
16. Where are these traps sent to?
17. How can I send a particular trap to selected destinations?
18. When I run the agent it runs and then quits without staying around. Why?
19. After a while the agent stops responding, and starts eating CPU time. Why?
20. How can I stop other people getting at my agent?
21. How can I listen on just one particular interface?
22. The agent is complaining about 'snmpd.conf'. Where is this?
23. Why does the agent complain about 'no access control information'?
24. How do I configure access control?
25. How do I configure SNMPv3 users?
26. The 'createUser' line disappears when I start the agent. Why?
27. What's the difference between /var/net-snmp and /usr/local/share/snmp?
28. My new agent is ignoring the old snmpd.conf file. Why?
29. Where should the snmpd.conf file go?
30. Why am I getting "Connection refused"?
31. Why can't I see values in the UCDavis 'extensible' or 'disk' trees?
32. Why can't I see values in the UCDavis 'memory' or 'vmstat' tree?
33. What do the CPU statistics mean - is this the load average?
34. How do I get percentage CPU utilization using ssCpuRawIdle?
35. What about multi-processor systems?
36. The speed/type of my network interfaces is wrong - how can I fix it?
37. The interface statistics for my subinterfaces are all zero - why?
38. Does the agent support the RMON-MIB?
39. What does "klread: bad address" mean?
40. What does "nlist err: wombat not found" (or similar) mean?
41. What does "Can't open /dev/kmem" mean?
42. The system uptime (sysUpTime) returned is wrong!
43. Can the agent run multi-threaded?
44. Can I use AgentX (or an embedded SNMP agent) in a threaded application?