From Net-SNMP Wiki

What traps are sent by the agent?

The agent sends a 'coldStart(0)' trap when it first starts up, and an enterprise-specific trap 'nsNotifyShutdown' (or 'ucdShutdown') when it stops. It can also be configured to send an 'authenticationFailure(4)' trap when it receives an SNMPv1 request using an unknown community name. The Net-SNMP agent generates an enterprise-specific trap 'nsNotifyRestart' (rather than the standard 'coldStart(0)' or 'warmStart(1)' traps) on receiving a HUP signal - typically after being re-configured.

The agent does not send 'linkUp' or 'linkDown' traps by default. It can be configured to do this using the directive 'linkUpDownNotifications'. See the 'snmpd.conf(5)' man page (under ACTIVE MONITORING) for details.

Similarly, it does not generate traps by default when one of the monitored characteristics (disk usage, running processes, etc) enters or leaves an error state. This can be configured using the 'defaultMonitors' directive (again documented under ACTIVE MONITORING).

Note that these facilities are only available with the v5 Net-SNMP agent, and are not supported by the v4 UCD agent.

   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' and 'pass'?
8. What's the difference between AgentX, SMUX and proxied SNMP?
9. What about 'dlmod' - what's that about?
10. Which should I use?
11. Can I use AgentX when running under Windows?
12. Can I use AgentX (or an embedded SNMP agent) in a threaded application?
13. How can I run AgentX with a different socket address?
14. How can I turn off SMUX support?
15. How can I combine two copies of the 'mib2' tree from separate subagents?
16. What traps are sent by the agent?
17. Where are these traps sent to?
18. How can I send a particular trap to selected destinations?
19. When I run the agent it runs and then quits without staying around. Why?
20. After a while the agent stops responding, and starts eating CPU time. Why?
21. How can I stop other people getting at my agent?
22. How can I listen on just one particular interface?
23. How do I configure access control?
24. I don't understand the new access control stuff - what does it mean?
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. Why am I getting "Connection refused"?
30. Why can't I see values in the UCDavis 'extensible' or 'disk' trees?
31. Why can't I see values in the UCDavis 'memory' or 'vmstat' tree?
32. What do the CPU statistics mean - is this the load average?
33. How do I get percentage CPU utilization using ssCpuRawIdle?
34. What about multi-processor systems?
35. The speed/type of my network interfaces is wrong - how can I fix it?
36. The interface statistics for my subinterfaces are all zero - why?
37. Does the agent support the RMON-MIB?
38. What does "klread: bad address" mean?
39. What does "nlist err: wombat not found" (or similar) mean?
40. How about "Can't open /dev/kmem"?
41. The agent is complaining about 'snmpd.conf'. Where is this?
42. The system uptime (sysUpTime) returned is wrong!
43. Can the agent run multi-threaded?