Ahigh-speed Internet connection is a thing of beauty, especially when it’s shared with everyone in your home or office over your network. After your network is set up and running smoothly, consider whether you want to share that connection through hardware or software as well as what sort of security you’ll need to protect everyone on your network. In this article, I discuss all the possibilities including the whiz-bang Virtual Private Networking (VPN) feature and show you how to set up Internet connection sharing within Windows XP.

Why Share Your Internet Connection?

“Don’t I need a separate Internet connection for each PC on my network?” Actually, you’ve just answered your own question: That network that you’ve installed allows for all sorts of data communications between PCs, including the ability to plug in to a shared connection. I should note here that it is indeed technically possible to share a dialup Internet connection by using the software connection-sharing feature in Windows XP. However, I don’t think that you’ll be satisfied with the results. (Sorry, that dialup connection won’t provide enough horsepower to adequately handle more than one computer.) Therefore, I’m going to assume for the rest of this article that you’re already using either a digital subscriber line (DSL) or a cable modem Internet connection. Here’s a list of advantages that help explain why Internet connection sharing whether through a program or a dedicated hardware device is so doggone popular these days:

-  It’s cheap. As long as your Internet service provider (ISP) allows you to share your broadband DSL or cable modem connection, you’ll save a bundle over the cost of adding completely separate connections for multiple machines in your home or office. (Naturally, this is the major advantage.)

-  It’s convenient. With a shared Internet connection, other PCs on your network are easy to configure, and each is content as a sleeping cat. Each PC on your network operates just as if it were directly connected to your DSL or cable modem.

-  It offers centralized security. With a firewall in place either running on the PC (if you’re sharing through software) or on the device itself (if you’re sharing through hardware) you can protect the Internet activity on all the PCs on your network at one time.

-  It’s efficient. Most folks whom I talk to are surprised that a shared Internet connection is so fast even when multiple computers on your network are charging down the Information Superhighway at the same time. A connection shared through a dedicated hardware device, however, will always be faster than a connection shared through software. Keep that in mind. Speaking of convenience and efficiency, I should also mention that many hardware sharing devices also double as Ethernet hubs or switches. This allows you to build your entire home or office network around one central piece of hardware rather than using a separate hub and a PC running a software sharing program.

Sharing through Software in Windows XP

If you decide to use the built-in Internet connection sharing (ICS) feature of Windows XP, first double-check that you already have everything in this list:

-  A working Ethernet network.

-  A working broadband Internet connection to one of the PCs on your network. Okay, you can use ICS with a dialup connection as well, but everything will be much faster with a DSL or cable connection.

-  An installed copy of Windows XP on the PC that’s connected to the Internet. This PC will also need two network cards installed one that leads to the network hub, and one that leads to the cable or DSL modem. Because many flavors of network cards exist (using many different connections, like USB, PC Card, and the more traditional internal adapter card), follow the installation instructions provided by the card manufacturer to add both cards to your PC. Everything shipshape? Good. Follow these steps to share that existing Internet connection with the other computers on your network:

1. Choose Start -> Connect To, and then right-click the connection that you want to share and choose Properties. The An Example ISP Properties dialog box appears.

2. Click the Advanced tab to display the settings

3. Select the Allow Other Network Users to Connect through This Computer’s Internet connection check box. • If you are sharing a dialup connection, I recommend enabling automatically dialing. If necessary, select the Establish a Dial-up Connection Whenever a Computer on My Network Attempts to Access the Internet check box. (Keep in mind, however, that this can wreak havoc on a voice call.) • To allow other network users to control the shared connection as in disconnecting it then select the Allow Other Network Users to Control or Disable the Shared Internet Connection check box.

4. Click OK to save your changes and return to the Windows XP desktop. Windows XP indicates that a connection is shared by adding a friendly looking cupped hand under the connection icon.  Of course, your IP addresses will be different from those in the figure, but it should help you understand how everything will fly.

Sharing through Hardware

As I mention earlier, I personally think that a hardware sharing device is somewhat preferable to sharing a connection through software. For example, with a software solution  -  You end up with at least one PC on your network that must always remain on if anyone wants to use the Internet.  -  You’ll notice a significant slowdown on the sharing PC when several other PCs are using the Internet.  -  You still need a hub, switch, or wireless base station. With a hardware device, all the PCs on your network can concentrate on their own work, eliminating the need to leave a PC running constantly as an “Internet server.” (After all, a PC that’s capable of running Windows XP at a decent clip is an expensive resource compared with an investment of $50–$100 on a hardware sharing device.) In this section, I familiarize you with the two different types of hardware sharing devices.

Wired sharing devices

For those PC owners who either already have a traditional wired Ethernet network or those who are considering building one a device like the Perhaps I should be a little more specific in my description. (Not even Google will return much if you search for switch-firewall-DHCP-server-sharing-thing.)

The illustrated device is actually a cable/DSL router with a four-port switch. For an idea of why hardware sharing is so popular, look at what you get in one small tidy box selling online for a mere $50:  -  A built-in, four-port Ethernet 10/100 switch into which you can plug four PCs (to start with) directly into the router for an instant Ethernet network.  -  A direct-connect port for your DSL or cable modem, which can also be used as a wide area network (WAN) connection to hook the device to an existing external network.  -  A DHCP server, providing near-automatic network configuration for the PCs hooked into the device.  -  The ability to block certain Internet traffic (both coming in and going out) as well as the ability to lock out individual PCs from Internet access.  -  An easy-to-use, Web-based configuration screen, which can be used on any PC connected to the router.  -  Built-in NAT functionality. (I dive into NAT in the next section.) Pretty neat, huh? Remember, this device is used in tandem with your existing cable or DSL modem, which is typically included by your ISP as part of your Internet subscription (but you might be paying more because you’re renting the modem). I should also note that you can get a similar device with all these features and a built-in DSL or cable modem. Because you won’t be charged a monthly rental for a modem, you can thumb your nose at your ISP and save money in the long run. (Please avoid mentioning my name when you gleefully return your modem to your ISP.) Naturally, the setup procedure for each device on the market is different, but here’s a sample of what’s in store when you take your new Internet sharing router out of the box: 1. If you’re currently running a typical stand-alone network switch or hub, you can either unplug all the existing computers and put them on the new box, or you can connect the WAN port from the existing hub into one of the ports on the Internet sharing device. The device manual will tell you how to take care of the latter method. If you’re setting up a new network, naturally, you’ll just connect each Ethernet cable directly to the sharing device.

2. Plug the power supply from the sharing device into your AC socket.

3. Configure one of the PCs on your new network with the default network settings provided by the device manufacturer.

4. Run Internet Explorer on the PC that you configured in the last step and use the Web-based configuration utility to finish configuring the device. That’s it! If you’re running a typical home or home office network, you’ll likely keep the default settings for everything. For an idea of just what kind of power you can wield over your network as you share your Internet connection, take a gander at the sidebar titled, “What the Sam Hill does that mean?” Luckily, you probably won’t have to use any of those optional settings, but it’s good to know that they’re there.

Wireless sharing devices

Most folks think that sharing an Internet connection over a wireless network must be harder to set up than a traditional wired network and that it’s likely to be a tremendous security risk as well. I’m happy to tell you that both preconceptions are wrong. Wireless connection sharing with a hardware device is as simple to set up as the wired device that I discuss in the preceding section. And, with the settings that I discuss in, Article 18, you’ll make it very difficult (if not impossible) for someone to hack his way to your network or your Internet connection. As an example of a truly versatile all-in-one Internet sharing device, check out the device. It’s got the antenna that marks it as a wireless switch, but what you don’t see is that it also sports four 10/100 Ethernet ports on the back for your old-fashioned wired network. Yep, you guessed it, this is just plain neat: It can accommodate multiple 802.11b wireless connections and four wired connections, all at the same time! As you might expect, the cost on this puppy (about $200 online) is much higher than the wired-only device (see the preceding section). Another factor is the speed of the wireless connection; as you can read in, Article 18, you’ll pay much more for the speed of an 802.11g device. (And yes, if you’ve decided to opt for a wireless-only network, you can find a cheaper wireless sharing device that doesn’t include any of those silly “antique” wired ports.) Wireless adapter cards (including the USB and PC Card varieties) are much more expensive than standard wired adapter cards, too. As I mention in, Article 18, don’t forget to demand a wireless sharing device that offers 128-bit Wired Equivalent Privacy (WEP) private encryption. Anything less, and your wireless network will be much easier for outsiders to hack.

Why You Need NAT

Okay, I know I’ve been harping about NAT (short for Network Address Translation) on and off for several pages now. You know that it’s important, but what does it actually do? If your Internet sharing device (or your Internet sharing software) supports NAT, a number of different PCs each with a different Internet Protocol (IP) address are masked behind the single IP address that’s assigned to your cable or DSL modem by your ISP. No one can tell what individual IP addresses are used behind your NAT device. In order to hack a PC on your system, someone on the outside (meaning elsewhere on the Internet) has to know the IP address of an individual computer on your system, and NAT prevents the intruder from learning just that. Instead, the only IP address that’s visible is the modem/Internetsharing device itself. Plus, a NAT blocks the most common weapon in the hacker arsenal: probing “port sniffers” that hunt for open, unprotected ports across the Internet. Note that NAT isn’t a complete firewall in and of itself. But when your connection-sharing hardware or software uses NAT in conjunction with a commercial firewall program such as Norton Personal Firewall (www.symantec.com), you’ve effectively shut the door on Internet intruders! By the way, the built-in Windows XP firewall has NAT built in, naturally.