How to add a permanent static route in Ubuntu and CentOS

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In ubuntu/CentOS you can add a static route, but if its temporary it won’t withstand a network restart/reboot/powercycle . So we need to add it permanent/persistent .

To add a temporary route in ubuntu , you can run the below command , here 192.168.10.0 network is routed via 192.168.1.1 gateway . You will need this rule only if you are not doing a persistent rule .

route add -net 192.168.10.0 netmask 255.255.255.0 gw 192.168.1.1 eth0

To make this a permanent route, use your favorite editor and edit the /etc/network/interfaces file

nano /etc/network/interfaces

Add the following rule :

up route add -net 192.168.10.0/24 gw 192.168.1.1 dev eth0

So once the route is added, it is better to restart the network manager but if you have multiple interfaces and in a production enviornment , you can just restart the specific interface

ifdown eth0 && ifup eth0

To create a temporary route in CentOS :

ip route add 192.168.10.0/24 via 192.168.1.1 dev eth0

So in CentOS the network file is different. To create route for a specific interface, we need to create a route file forthat interface in the network-scripts location . In this case , eth0 is our interface

nano /etc/sysconfig/network-scripts/route-eth0

192.168.10.0/24 via 192.168.1.1 dev eth0

service network restart or
ifdown eth0 && ifup eth0