what-is-networkingwhat-is-networking

Viewing the existing routing table

Before we embark on adding or deleting routes, it’s prudent to check the existing default routes on a system. To do so, simply launch your terminal and issue the command:

$ ip route show
Or
$ ip route list

 Similar statistics can be displayed using route command,
$ route -n

Or simply,
$ route 

Adding a static route using IP command

Suppose you want to take a backup of a Linux machine and push the backup file to another backup server in the subnet 10.0.2.0/24. However, for one reason or the other, you cannot reach the backup server  via the default gateway. In this case, you will have to create a new route for backup server subnet via another IP, say 192.168.43.223 via the interface enp0s3.

The command for this will be

$ sudo ip route add 10.0.2.0/24 via 192.168.43.223 dev enp0s3

Where:

  • 10.0.2.0      ->             is the network you want to connect to
  • /24              ->             is the subnet mask
  • 192.168.43.223 ->    is the IP through which we will reach the server
  • enp0s3       ->            is the network interface

You can confirm whether new static route add been in route table using β€œip route show” command.

$ sudo ip route show

To add the specific IP of the backup server, say 10.0.2.15 run the command:

$ sudo ip route add 10.0.2.15 via 192.168.43.223 dev enp0s3

Once again, you can check the routing changes to see if the changes exist using the ip route show command:

$ ip route show