Setting up Internet Connection Sharing (Windows XP)

Setting up Internet Connection Sharing (Windows XP)

Intended For

Windows XP only

The Internet Connection Sharing service built-into Windows XP is nearly identical to its counterpart in Windows 2000, and is therefore very easy to set up. If you have Windows 98, Windows Me, or Windows 2000, return to the Internet Connection Sharing main page.

ICS allows two or more networked computers to share a single Internet connection, and it's not that hard to set up, as long as you do it properly. If you perform the following steps, in order, you should be able to get it right the first time.

Note: don't be intimidated by the length of this article. It shouldn't take you more than 20 minutes or so to set up ICS (assuming you have the proper hardware installed). A lot of what's here covers various 'what if' situations.

Jump to:

What You Need

Cabling Overview

Setting Up the Host

Setting Up the Clients

Troubleshooting

More Information

What You Need

In order to get ICS (Internet Connection Sharing) to work, you'll need the following items:

At least two computers.

A functioning ethernet card properly installed in each computer. Refer to the documentation that comes with your ethernet cards for proper driver installation and setup.

If you're sharing a DSL, cable modem, or other ethernet-based Internet connection, the computer with the connection must have two ethernet cards installed. (Microsoft doesn't tell you about this one!)

The network must be cabled correctly. 10base-T or 100base-T, category-5 patch cables, and an ethernet hub are recommended. If you have only two computers, you can forgo the hub, and use a Category 5 crossover cable instead.

One of the computers must have a dial-up internet connection, properly set up, or a high-speed connection, such as DSL, a cable modem, or T1.

There is no minimum connection speed, but you should keep in mind that when two users are downloading using the shared connection simultaneously (the worst-case scenario), each user will experience half of the original performance. In other words, you probably don't want to bother sharing a 14.4k analog modem connection.

The computer with the Internet connection must be running a version of Windows that supports Internet Connection Sharing. (Note that the directions on this page are for Windows XP; if you have another version of Windows, return to the ICS main page and view the directions appropriate to your OS.)

Cabling Overview

Once you have the correct protocols and drivers set up on the host and each of the clients, the next step is to figure out the cabling. Without the internet connection, your network should look something like this:

(Naturally, the number of PCs and printers on your network will probably be different.) The next step is to figure out how the Internet Connection will be wired. For ICS to work, your setup should look like this:

Note that the Internet connection can be in the form of a phone cable plugged into an analog modem, an ethernet cable plugged into a second network card, or some other connection plugged into the appropriate card.

Setting Up the Host

The first step to setting up ICS is to configure the host, the computer with the Internet Connection that will be shared. All the other computers are called 'Clients,' and are discussed in the following section.

Open Network Connections in Control Panel, or right-click on the My Network Places desktop icon and select Properties.

Here, you should have at least two connections listed: one for your Internet Connection, and one for your Local Area Connection. If they're not there, your network is not ready - install the proper hardware and software (described above) and try again.

By default, the available connections will named for the network adapters they represent; to make things easier, I recommend renaming them as shown in this screenshot:

Right-click on the entry corresponding to your Internet connection, and select Properties (see this article if you're using PPPoE).

Among the installed components listed in the General tab, the following should be checked here

Client for Microsoft Networks

Internet Protocol (TCP/IP)

If you don't see one or more of these items, you'll need to add them by clicking Install.

If there are extra entries, just ignore them. The exceptions are NDISWAN or any ATM protocols - if you encounter a problem later on, you might have to remove these to use ICS.

If you have any other Internet sharing solutions (more information) installed on any of the machines, make sure they have been removed or disabled on each machine.

At this point, it's a good idea to make sure your current Internet connection is operational by testing it (load a web page or something). If all is well, then you can continue.

Choose the Sharing tab, and turn on the Enable Internet Connection Sharing for this connection option.

There's nothing useful behind the Settings button, so just click Ok when you're done. That's it! (Most likely, Windows will not make you restart, although if you are prompted, do so now.)

Setting Up the Clients

The client machines don't require any special software; just a properly installed, network-capable operating system (such as Windows 95/98/Me/NT/2000/XP - see What You Need for details), or even Unix, FreeBSD, Linux, or Mac. Do the following for each client machine that will be using the shared connection: (Note that these details are for Windows XP clients; check out the main ICS page for other platforms.)

Open Network Connections in Control Panel, or right-click on the My Network Places desktop icon and select Properties.

Here, you should have at least one connection listed for your Local Area Connection. If it's not there, your network is not ready - install the proper hardware and software (described above) and try again. Any other connections can be ignored, although you may want to disable them for now (right-click and select Disable).

Right-click on the entry corresponding to your local area connection, and select Properties.

Among the installed components listed in the General tab, the following should be checked here

Client for Microsoft Networks

Internet Protocol (TCP/IP)

Next, highlight the Internet Protocol (TCP/IP) entry and click Properties.

Choose the Obtain an IP address automatically and Obtain DNS server address automatically options.

Click Advanced, and make sure the various lists in the IP Settings, DNS, and WINS tabs are all empty.

Click Ok and then Ok again when you're done. (Most likely, Windows will not make you restart, although if you are prompted, do so now.)

Once these steps have been performed, Internet Connection Sharing should be in effect, and all connected and properly-configured client computers should have access. You can test each client by loading a web page or using some other Internet application (e.g. Ping, telnet, etc.).

Troubleshooting

Ideally, you shouldn't have to install any software or do any more configuration on any of the clients. However, this isn't an ideal world, so if this doesn't work as expected, try the following:

You know that ICS is working if you have Internet access on at least one client. If you don't, the first thing to do is to make sure the Internet connection is working on the host computer. Conversely, if one client is working, and another isn't, it's definitely a problem with that client.

If you're sharing an ethernet-based connection, such as DSL or a cable modem, make sure the host computer has two network cards.

Go back through Setting Up the Host and Setting Up the Clients and make sure all the necessary components and protocols are properly installed.

Check to see if you have any firewall software installed on the host or clients; for that matter, check for any installed software or settings that might be inappropriate to the type of connection you have.

If you're using special connection software for use with your DSL or cable (such as the feeble NTS Enternet 300 software), it's best to remove it and use Windows XP's built-in support for PPPoE. Also, if you find that you can't access certain websites from the client machines, see this article.

If all else fails, try uninstalling the two connections on the host computer, and then reinstalling the necessary drivers. (This has been known to work on more than one occasion.)