The best way is to edit your snmpd.conf file - not sure where it is on your server but try /etc/snmp/snmd.conf)
this one use v2c readonly to any thing that can get to the server over UDP 161 (you need to protect it with iptables or some type of firewall)
rocommunity public
sysLocation 1234 DownToen Street
sysContact Lab Department - (555) 555-5555
To protect a little bit more, you can add an IP after the community string
More help can be found below
