Add static route to linux

add a remote host

remote host 192.168.1.20
local gateway 10.1.1.20
route add -host 192.168.1.20 gw 10.1.1.20

add a remote network

route add -net 192.168.98.42 netmask 255.255.255.255 gw 192.168.99.1

check the route 

route -n

Delete a route

route del -net 10.41.41.0 netmask 255.255.255.0 gw 10.41.42.8

route add -net 192.56.76.0 netmask 255.255.255.0 dev eth0

adds a route to the network 192.56.76.x via "eth0". The Class C netmask modifier is not really necessary here because 192.* is a Class C IP address. The word "dev" can be omitted here.

To make the routing information persistent, add the “route add” line as seen above into the /etc/rc.local file.
Sample /etc/rc.local file.
or /etc/rc.d/rc.local

touch /var/lock/subsys/local
route add -net 10.41.41.0 netmask 255.255.255.0 gw 10.41.42.8