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Network Services—Local Network ServicesSimple Network Management Protocol(SNMP)SNMP is a protocol to monitor and control network attached devices. SNMP agentsthat run on the devices can provide status information about the device uponrequest, or even send TRAP messages to specific hosts, when an event occurs. SNMPcan also be used to manage devices over the network by setting the given parameteron the device.SNMP is a client/server protocol. A SNMP server (or agent) is a piece of softwarethat runs on hosts and keeps one or more databases of almost live information aboutthe host. These databases are called Management Information Bases (MIBs).On the other hand, the SNMP client queries SNMP servers/agents for information.This information can be used in a Network Management System (NMS) to monitorthe status of the device, or can be used to draw statistics graphs.There are various open-source SNMP suites available that can be used in FreeBSD.This chapter discusses two important SNMP implementations in FreeBSD asshown here:• Net-SNMP, that is available via ports system, is a very popular open-sourceSNMP toolkit.• bsnmpd is a light-weight SNMP agent that is available in FreeBSD'sbase system.bsnmpdThe bsnmpd(1) daemon is a very light-weight SNMP daemon that is supposed toserve only the basic SNMP MIBS, and the other MIBS through loadable modules. Thebsnmpd(1) is available in FreeBSD base system, out of the box.Setting up a basic SNMP server using bsnmpd is pretty straightforward:bsnmpd_enable="YES"Adding this line to /etc/rc.conf file will enable the daemon so that it is startedautomatically, upon system start up. You should then start the daemon, manually,for the first time:# /etc/rc.d/bsnmpd startAnd you are set.[ 248 ]