my nexus core switches are not communicating witn SNMP

jaguemon

snmp-server user is configured correctly with authentication and privacy and still snmp is failing - no ACL blocking. The switch and the solarwinds server can ping each other. Anybody has any idea what this could be? Thanks for your help!

Martin_Crothers

Hi @jaguemon,

Try the credentials with the SNMP Walk tool.  If you’re receiving an SNMP error “Unknown user name”, but you’re certain that the username is correct, the other aspects that may be causing it are:

• SNMP Permitted Managers
  This aspect is like an ACL.  It indicates which managers the agent will reply to.
• VACM
  This aspect configures the OIDs that the managers may request.

I’m not a Nexus guy, so I’m not fluent in configuration on those types of systems.

Beyond SNMP walk you could also decrypt the traffic in Wireshark.  If you set up a capture filter for the one node you’re testing from the polling engine you’re attempting to add the node to, or run the walk from, you can also add the SNMP credentials in Wireshark and look at the responses to get an idea of the cause of the error.

Plain text responses on auth errors are:

• 1.3.6.1.6.3.15.1.1.3.0, value = unknown username (or the above issues related)
• 1.3.6.1.6.3.15.1.1.5.0, value = 18: wrong authentication password
• 1.3.6.1.6.3.15.1.1.5.0, value = 18: wrong authentication protocol

If the packet returns encrypted but Wireshark couldn’t decrypt it, then there is a problem with the Privacy (aka Encryption) protocol or password.