FAQ:Applications 11

How do I use SNMPv3?

The simplest form of SNMPv3 request is unauthenticated and unencrypted (noAuthNoPriv). It simply requires a user name, and would look something like:

       snmpget -v 3 -l noAuthNoPriv -u dave localhost sysUpTime.0

However this approach foregoes the security protection which is the main advantage of using SNMPv3 (and the agent must also be explicitly configured to allow unauthenticated requests from that user).

The most common form of SNMPv3 request is authenticated but not encrypted (authNoPriv). This specifies the pass phrase to authenticate with:

       snmpget -v 3 -l authNoPriv -u dave -A "Open the Door"
                               localhost sysUpTime.0

A fully secure (i.e. encrypted) request (authPriv) would also specify the privacy pass phrase:

       snmpget -v 3 -l authPriv -u dave -A "Open the Door"
                       -X "Bet you can't see me"  localhost sysUpTime.0

In practise, most of these would probably be set via configuration directives in a personal $HOME/.snmp/snmp.conf file (note, not the agent's snmpd.conf file).
The equivalent settings for the third example would be:

       defSecurityName         dave
       defSecurityLevel        authPriv
       defAuthPassphrase       "Open the Door"
       defPrivPassphrase       "Bet you can't see me"

If the AuthPassphrase and the PrivPassphrase are the same, then you can use the setting

               defPassphrase   "Open the Door and see me"

instead.

See the AGENT section for how to configure the agent to respond to SNMPv3 requests.

   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?