How to Troubleshoot SNMP

Agent Issues

Make sure an SNMP agent is actually running and accessible from the Zenoss server. You can do so by simply issuing the following command on the Zenoss server:

snmpwalk -c YOUR_COMMUNITY_STRING -v 1 YOURDEVICE_IP (if you don't know your community string try "public")

You are in trouble if the above command returns:

Timeout: No Response from 1.2.3.4

This means that the device isn't answering to your SNMP request, this could have multiple reasons:

Linux

There is no SNMP daemon running on the target device. You can check this by issuing

netstat -an |grep -i udp

see if there is an entry that looks like the one below.

udp 0.0.0.0:161 0.0.0.0:*

If so the agent is running but Zenoss can't get the information for a different reason.

The SNMP daemon is running but the configuration doesn't allow any connections. Put "rocommunity public" into /etc/snmp/snmpd.conf to give read access to Zenoss. Look here for more details on how to configure Net-SNMP.

Is there a Firewall on the target device or between the Zenoss server and the target device. You can use tcpdump to debug this issue.

Windows

Check to see whether the target device has an SNMP agent installed and running:

If you have a running SNMP agent as shown above you need to make sure to set access permissions to the agent accordingly:

The above configuration shows the current machines community string is public and it allows connections from any host. This can be adjust as needed of course.

Also one should check to see whether the Windows Firewall allows incoming connections to the SNMP agent:

Note: Running the default Microsoft SNMP agent will provide only a limited set of information to you. In order to get the largest set of information from your Windows systems we suggest you use SNMP Informant instead. Check here to see how to install SNMP remotely on Windows.