FAQ:Applications 14

Why can't I change sysLocation (or sysContact)?

There is one final possibility to consider for why a SET request might be rejected.

The values for certain MIB objects (including 'sysLocation' and 'sysContact') can be configured via the 'snmpd.conf' file. If this is done, then these particular objects become read-only, and cannot be updated via SET commands, even if the access control settings would otherwise allow it.

This may seem perverse, but there is good reason for it. If there is a configuration setting for one of these objects, then that value will be used whenever the agent re-starts. If the object was allowed to be updated using SET, this new value would be forgotten the next time the agent was re-started.

Hence the Net-SNMP agent rejects such requests if there's a value configured via the 'snmpd.conf' file. If there isn't such a config setting, then the write request will succeed (assuming suitable access control settings), and the new value will be retained the next time the agent restarts.

   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 query a string-indexed table value - why?
17. How should I specify string-index table values?
18. How do I send traps and notifications?
19. How do I receive traps and notifications?
20. How do I receive SNNMPv1 traps?
21. Why don't I receive incoming traps?
22. My traphandler script doesn't work when run like this - why not?
23. How can the agent receive traps and notifications?
24. How big can an SNMP request (or reply) be?
25. How can I monitor my systems (disk, memory, etc)?
26. Applications complain about entries in your example 'snmp.conf' file. Why?
27. OK, what should I put in snmp.conf?
28. How do I specify IPv6 addresses in tools command line arguments?