An SNMP master is a server process running the SNMP message daemon. A true SNMP master can poll agents or receive traps. The SNMP master provides a central location where network monitoring can be performed from. The master contains a memory copy of all MIB objects that it understands, typically compiled from one or more text files that describe the object being polled or name of the object indicated in the received trap. SNMP master servers are usually integrated with other software that performs notification and alert functions as well as performing statistical calculations.
An SNMP master server listens on UDP port 162 for traps and polls equipment on port UDP 161. The network administrator can enter human readable names such as .iso.org.dod.internet.mgmt.mib-2.system and the master server will translate this to the numerical value .1.3.6.1.2.1.1.1 which the agent should recognize and respond to if it supports SNMP 2c or later.
Master servers support various versions of SNMP. The latest SNMP master servers support SNMP v3, while older servers may support only SNMP v2c or lower.