Internetworking

Connecting several computers to the internet with 1 ISP account


Use Case

I have 1 girlfriend and 2 computers. We both have an e-mail account with a free Internet Service Provider (ISP). To avoid having to fight who can use the computer to read, download or sent mail or browse the web, it would be good if we could each use a separate computer. This also avoids her messing up my configuration - or me rendering her computer useless with too much trial and error (especially error).

Old computers are easy to come by : as people and companies continue to buy new PC's to match 'today's requirements' in HD space, RAM and CPU speed, there's agrowing second hand market where you can get 5 year old computers for next to nothing, and they'll still be sufficient for every day use.

This allows you to collect a couple of usefull machines, make a home netwok, experiment with networking, setting up servers and clients, ...
Remains the problem of connecting several computers to the internet. Moving the modem from one PC to another according to need, is not an elegant solution. My girlfriend would find that too much of a poor man's way of doing things. It may also involve screwdrivers.

Solutions

There are several ways to do connect your computers to the internet. According to this paper, there are at least 3 :

Number 4 would be : Microsoft Windows' Internet Connection Sharing. This is in fact routing and address translation software that runs on Windows systems. It's free and easy to set up, if you are using Windows.

TCP/IP network

In any case, you'll need a network, and as you're going to connect it to the internet, which uses TCP/IP, you might as well just use TCP/IP as protocol on your local network. Makes your life a lot easier.

If you need a brief intro in setting up a home network and setting up TCP/IP, you may have a look at this introduction.

Connecting a LAN to the internet

Proxy servers

software routers

Freesco and Winroute are not only (software) routers, but firewalls as well.