From Net-SNMP Wiki

How do I handle traps and notifications?

Handling received traps is done using the tool 'snmptrapd'. This can log these traps via the syslog mechanism:

       snmptrapd -Ls 7         (log to 'LOCAL7')
       

printed to standard output

       snmptrapd -f -Lo

or pass them to an external command. This last approach uses a 'traphandle' directive in the configuration file 'snmptrapd.conf'. A typical file might look something like:

       traphandle .1.3.6.1.6.3.1.5.1       page_me up
       traphandle .1.3.6.1.4.1.2021.251.1  page_me up
       traphandle .1.3.6.1.4.1.2021.251.2  page_me down
       traphandle default                  log_it

where 'page_me' and 'log_it' are the command to be run. (You probably need to specify full pathnames, to ensure that the commands will be found. They're just short here for readability).

Note that the first entry uses the OID corresponding to the SNMPv1 'coldStart' trap. See the co-existence RFC (RFC 2576) for details of mapping SNMPv1 traps to SNMPv2 OIDs.

Starting with net-snmp 5.3, snmptrapd will no longer automatically accept all incoming traps. It must be configured with authorized SNMPv1/v2c community strings and/or SNMPv3 users. Non-authorized traps/informs will be dropped. Please refer to the snmptrapd.conf(5) manual page for details.

There's a tutorial with more details on the web site at http://www.net-snmp.org/tutorial-5/commands/snmptrap.html

   FAQ:Applications
   

1. How do I add a MIB?
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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?
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10. Why do I sometimes get "End of MIB" when walking a tree, and sometimes not?
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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?