How to set up a LAN (Part 2: The software (using Linux))
Okay, so you've got your network cards connected. Now you want to get your computers communicating with each other. How do you do that? Well, obviously it depends on what software you're using. On this page, I cover the first steps to configuring your network with Linux. (Other operating systems suck for networking.)
The very first thing you'll need to do is run the ifconfig command. Short for "interface configure", this command will configure your network interface; If nothing else, you need it to assign an address to your computer. Pick any computer on your network, and type this at the Linux prompt:
ifconfig eth0 192.168.0.1
This will set eth0 (your first and probably only Ethernet device) to have a local IP address of 192.168.0.1. Now other systems on the LAN can access it just by using that address. Run this same command on every computer on the network, adjusting the last number for each system so they all have their own unique address. (For example, the next computer would be 192.168.0.2, and so on.)
Once this is done, your computers can start communicating right away, using their very own IP addresses. Yes, it really is that simple. All you have to do is give each computer its address and the other systems will be able to find it. To test the connections and make sure they're working, try pinging some other systems with the ping command (to do this, just type ping ipaddress) and finger (type finger @ipaddress). If you get a response, the link is working fine, and you can share files among the systems through the use of FTP or rcp. You can also log into them remotely with telnet or rlogin. Have fun.