VMware ESX 4.1 and vCenter Server 4.1 Edition

vSphere Datacenter Administration Guide : Monitoring Your Virtual Infrastructure : SNMP and vSphere : SNMP Diagnostics

SNMP Diagnostics
Use SNMP tools to diagnose configuration problems.
You can use the following tools to diagnose problems with SNMP configuration:
Type vicfg-snmp.pl --server hostname --username username --password password --test at the vSphere command-line interface to prompt the embedded SNMP agent to send a test warmStart trap.
Type vicfg-snmp.pl --server hostname --username username --password password --show to display the current configuration of the embedded 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.