Internet Connection Sharing is a new function of Windows XP to allow multiple users to share one internet connection through one computer. In one sense, this makes the computer a ?router? or a ?proxy?, if you add Internet Connection Firewall (ICF), it makes it a firewall as well. If you are not familiar with those terms - it's ok. Basically, it allows one computer to act as the gateway or the doorkeeper to the Internet.
ICS functions on a network by routing all Internet traffic through one machine. This one machine needs a connection to the LAN and a connection to the Internet ? be it dialup, cable modem, DSL, ISDN, or other. In addition, ICS should not be used on a network with servers, DHCP, DNS, etc as it will conflict with those by acting like a DHCP server. So if you are at a workplace, you may not want to turn on ICS without asking someone first.
For the techies among us, this information may be handy: ICS is inflexible in many regards ? not allowing you to change its initial static IP address or those in the range that it assigns to client computers. It assigns your LAN connection an IP of 192.168.0.1 and then other clients on your network receive 192.168.0.x addresses.
For everyone else: if you have a hardware router like a Linksys on your cable connection, ICS probably isn't for you. It may conflict with your existing setup. Otherwise, if you just have a cable or DSL modem and want to share it among all your computers without buying additional hardware, Internet Connection Sharing may be for you.
You will need two network connections on your computer - one for the Internet and one for your internal network (LAN).
The first step in setting up Internet Connection Sharing is to start the Network wizard. You can accomplish this by going to Start > Programs > Accessories > Communications > Network Setup Wizard. The alternative method to starting the wizard is to open the Control Panel and open Network Connections.
Click on Set up a home or small office network in your ?Network Connections.?
Click Next.Click Next.
Choose ?This computer connects directly to the Internet?? and click Next.
Choose your Internet connection from the list and choose Next.Enter a Computer Description and click Next.
Enter your workgroup name and click Next.
Click Next to setup your connection.You can also setup Internet Connection Sharing by right-clicking on your Internet connection and choosing Properties. Click on the Advanced tab and check the All other network users to connect? checkbox and click OK.
In order to use ICS on a machine, you must configure it. On the client machine (Windows XP), you will need to start the Network Setup Wizard.
Choose ?This computer connects to the internet through another computer?? and click Next.
Describe your computer and click Next.Enter the name of your network. Click Next.
Click Next. The wizard will complete, click Finish and you are all set!