The Simple Network Management Protocol (SNMP) daemon will attempt to bind sockets to certain well-known User Datagram Protocol (UDP) and Transmission Control Protocol (TCP) ports, which must be defined in the /etc/services file as follows:
snmp 161/udp snmp-trap 162/udp smux 199/tcp
The snmp service must be assigned port 161, as required by RFC 1157. The /etc/services file assigns ports 161, 162, and 199 to these services. If the /etc/services file is being serviced off another machine, these assigned ports must be made available in the served /etc/services file on the server before the SNMP daemon can run.
The SNMP daemon reads a configuration file, /etc/snmpd.conf, on startup and when a refresh command (if the snmpd daemon is invoked under System Resource Controller control) or kill -1 signal is issued. This configuration file specifies the community names and associated access privileges and views, hosts for trap notification, logging attributes, snmpd-specific parameter configurations, and single multiplexer (SMUX) configurations for the SNMP daemon. See the /etc/snmpd.conf file for more information.