Network management is one of the important functionality in network Engineering. This paper proposes a methodology for security in SNMP managed sensor networks. McAfee is the platform used for implementing the security. It is mainly based on SNMP V3 which is the enhanced version of SNMP and it includes authentication.IEEE1451.4 TEDS is also incorporated to provide plug and play of sensor networks. SNMP is compactable with many kind of devices used in networking, So it provides a wide variety of devices to communicate in a network independent of the manufacturers. The proposed security method is applicable to many of the sensor devices.