The most common SNMP configuration on Linux/UNIX is by using the net-snmp package maintained by http://www.net-snmp.org/ (aka "the nice BSD folks"). Installing and configuring net-snmp varies slightly depending on the specific Linux/UNIX distribution you are working with.
On Linux servers with a large number of interfaces (ppp, dummy, bridge, etc.), the IF-MIB timer based stats collector can take a large amount of CPU processing. The new config option "include_ifmib_iface_prefix" takes a space separated string of ifname prefixes ("eth lo bridg") and will only include interfaces with these prefixes in the IF-MIB ...