2. route

In Linux, the routing table directs network traffic to its correct destination. While we've previously discussed viewing this table, you can also manually add or remove routes to control how data packets are forwarded. This is essential for configuring complex network setups or troubleshooting connectivity issues.

Using the Legacy route Command

The route command is a traditional tool for managing the routing table. While still functional, it is considered legacy, and the ip command is now preferred.

To add a new network route, you specify the network address, subnet mask, and the gateway (gw):

sudo route add -net 192.168.2.1/23 gw 10.11.12.3

To delete a route, use the del flag with the network address:

sudo route del -net 192.168.2.1/23

Modern Route Management with ip route

The ip route command is the modern and more powerful tool for network configuration in Linux. It offers a more consistent and extensive set of options for managing network interfaces and routes. Using the linux ip route command is the recommended practice for current systems.

To add a route with the ip route command in linux, you use the add action, specifying the destination network and the next hop via the gateway:

ip route add 192.168.2.1/23 via 10.11.12.3

To delete a route, you can use the delete action. You can specify the route in full or just the destination network if it's unique:

# Delete by specifying the full route
ip route delete 192.168.2.1/23 via 10.11.12.3

# Or, delete by specifying only the destination
ip route delete 192.168.2.1/23

Mastering the ip route command is a key skill for any Linux administrator responsible for network management.