Hi Santosh,
Follows these steps that i copied from a website. Should be ok.
Some people have asked how to enable SNMP on ESXi 5. The process is identical to how you would on ESXi 4.x. Here’s how:
1.Connect to your vMA instance through Putty, SecureCRT or whatever app you use.
2.Add the server: vifp addserver vs-esxi.vsential.com (This is only needed if you haven’t already added the target!)
3.Set your target: vifptarget -s vs-esxi.vsential.com
4.Configure SNMP Community: vicfg-snmp –communities vscomname
5.Configure SNMP Trap Host: vicfg-snmp –targets TrapHostIP@161/vscomname
6.Enable SNMP on the ESXi host: vicfg-snmp –enable
You can show the configuration by typing: vicfg-snmp –show
That’s it…now you can snmpwalk the host from the Trap host you configured earlier by typing: snmpwalk -v2c -cvscomname vs-esxi.vsential.com
You can check out VMware KB Article 1008065 for information on how to configure this as well which uses VMware vSphere RCLI instead of the vMA.