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