You can use SNMP tools to diagnose configuration problems.
Type esxcli system snmp test at the vSphere command-line interface to prompt the SNMP agent to send a test warmStart trap.
Type esxcli system snmp get to display the current configuration of the SNMP agent.
The SNMPv2-MIB.mib file provides a number of counters to aid in debugging SNMP problems. See SNMPv2 Diagnostic Counters.
The VMWARE-AGENTCAP-MIB.mib file defines the capabilities of the VMware SNMP agents by product version. Use this file to determine if the SNMP functionality that you want to use is supported.