How to configure Static routing in Linux

Static routes will be added usually through “route add” or “ip route” command. However, “route add” command configures routing on the runtime and doesn’t persist the configuration after a reboot. To make it persistent across reboots, you have to add it to /etc/sysconfig/network-scripts/route-<interface-file> . For example, static routes for the eth0 interface would be stored in the /etc/sysconfig/network-scripts/route-eth0 file. Here are the Steps to configure static routing in Linux.

To add static route using “route add” in command line:

# route add -net 192.168.100.0 netmask 255.255.255.0 gw 192.168.10.1 dev eth0

To add static route using “ip route” command:

# ip route add 192.168.100.0/24 via 192.168.10.1 dev eth1

Adding Persistent static route:

You need to edit /etc/sysconfig/network-scripts/route-eth0 file to define static routes for eth0 interface. This configuration will be persistent even after the server is rebooted.

GATEWAY0=192.168.10.1 NETMASK0=255.255.255.0 ADDRESS0=192.168.100.0

GATEWAY1=10.64.34.1 NETMASK1= 255.255.255.240 ADDRESS1=10.64.34.10

Save and close the file. Restart networking:

# service network restart

There are various ways to verify the routing table in Linux. Few commands are listed below:

# route –n
# netstat –nr
# ip route show