===== Adding a Network Route in Linux =====

As root:

==== Adding a Route ====

  route add -net 192.168.15.0 netmask 255.255.255.0 gw 192.168.1.1

First value is destination network address, then the destinsation's netmask and then your gateway for the destination network.

==== Adding a Default Gateway ====

  route add default gw 192.168.1.1

IP address is address of gateway machine.