Linux Shell Scripting Cookbook - Third Edition

Showing routing table information

It is common to have interconnected networks. For example, different departments at work or school may be on separate networks. When a device on one network wants to communicate with a device on the other network, it needs to send packets through a device which is common to both networks. This device is called a gateway and its function is to route packets to and from different networks.

The operating system maintains a table called the routing table, which contains the information on how packets are to be forwarded through machines on the network. The route command displays the routing table:

$ route 
Kernel IP routing table 
Destination      Gateway   GenmaskFlags  Metric  Ref  UseIface 
192.168.0.0 * 255.255.252.0 ...