There are numerous ways to add static routes in Linux (CentOS). The easiest way is via the terminal by using one of the following examples.
How to add a static route for a specific host in Linux.
route add -host 192.168.1.47 gw 192.168.10.1
route del -host 192.168.1.47 gw 192.168.10.1
How to add a static route for a specific network in Linux.
route add -net 192.168.1.0/24 gw 192.168.10.1
route del -net 192.168.1.0/24 gw 192.168.10.1
How to add a default gateway.
route add default gw 192.168.10.1
route del default gw 192.168.10.1
The best place to add the default gateway is in the file /etc/sysconfig/network which would then look something like the below.
NETWORKING=yes NETWORKING_IPV6=yes HOSTNAME=server.example.com GATEWAY=192.168.0.10
Also note that default gateways are added on a per interface level in their startup files located in /etc/sysconfig/network-scripts. Example: /etc/sysconfig/network-scripts/ifcfg-eth0
One of the places to add a static route so it is added each time you reboot the server is to add it to /etc/sysconfig/rc.local. Your rc.local file would then look something like the below.
#!/bin/sh # # This script will be executed *after* all the other init scripts. # You can put your own initialization stuff in here if you don't # want to do the full Sys V style init stuff. touch /var/lock/subsys/local # Static Routes /sbin/route add -net 192.168.1.0/24 gw 192.168.10.1 /sbin/route add -host 192.168.1.47 gw 192.168.10.1