Linux Routing

Why use Linux as a router? Its cheap. Linux has low hardware requirements. A properly configured P166 Mhz computer would have no problems routing for a T1 or cable/DSL connection.

How do I setup a router? Firstly you have to insure that your kernel has recognized each of your network cards. This can be done by typing ifconfig IE) ifconfig eth0 ifconfig eth1 ifconfig eth

What if my cards are not recognized by the kernel? You will then have to recompile your kernel or edit the rc.modules file. The rc.modules file simply runs during boot up and runs the modprobe command to search for compile modules. You should just have to uncomment the modules you wish to run.

A Sample Network

Review of networking Step 1 Identify the default routes for each of the routers. Pig Dog Hog Horse Otter Bear Elk Beaver

Review of networking Step 2 Identify each of the routes for each of the routers. Identify the interfaces Write the route command for each of the routes.

Adding a route To add a route to a network one would use the route command. To View Routing Tables one could use the netstat –rn command or the route command.

Adding/Deleting Network Routes route add -net /24 gw route del -net /24 gw

Adding/Deleting Host Routes Adding and Removing a specific host in Linux route add -host gw route del -host gw

Adding/Deleting Default gateways route add default gw route del default gw