Wireless Networks That Do More

Share Your Dial-Up Connection

Just about everyone agrees that the best way to share a broadband connection across your network is to use a router. Routers have gotten dirt-cheap, and you don't need to use an always-on host computer. On top of that, the extra security--provided by Network Address Translation (NAT), which conceals local Internet Protocol (IP) addresses from the Internet--comes free. But what happens if your shared broadband connection goes down unexpectedly for a long period, or if your ISP disappears? Sharing your dial-up connection is one option, but be forewarned: Setting it up can be cumbersome.

In this contingency plan, one computer acts as a temporary host so that every computer on the network can use the host's dial-up Internet connection. This is recommended only if you've already set up your network with a Dynamic Host Configuration Protocol (DHCP) server, which assigns a unique IP address to each networked computer.

When you need to share a dial-up connection, you must begin by disabling the router's DHCP server (most router configuration software has a DHCP tab where you'll find the Disable option). Assuming that the PC you intend to use as the host is running Windows 98 Second Edition or later, you can enable Windows' Internet Connection Sharing (ICS) for the dial-up connection.

The ICS utility is included in the default installation of Windows XP. But if your machine runs Windows 98 SE or Me, you'll likely have to install it: Fire up Control Panel, open Add/Remove Programs, and choose the Windows Setup tab. From the list of Windows components, select Internet Tools (or Communications, if the Internet Tools option doesn't appear); then click the Details button and check the Internet Connection Sharing checkbox to install ICS.

At this point, you'll have to use a wizard to establish an Internet connection. Decline the option to create setup disks for other computers on the network, and click the Finish button at the last wizard screen. Then restart the host PC and the other computers on your network. Click your dial-up connection on the host computer, and you should be able to share the connection. If not, on each client computer, right-click My Network Places or Network Neighborhood and choose Properties. On XP and 2000 clients, right-click the local area network connection and choose Properties. In the 'components' or 'items' list, select the TCP/IP entry (don't uncheck its checkbox) and then choose Properties. Make sure that Obtain an IP address automatically is selected, click OK twice, and close the window.

If the host is running Windows 2000 or XP, right-click My Network Places and select Properties. Then right-click your dial-up connection and select Properties. In 2000, select the Sharing tab, check Enable Internet Connection Sharing for this connection, leave Enable on-demand dialing checked, click OK, and close 'Network and Dial-up Connections'. For XP, select the Advanced tab, check all three Internet Connection Sharing options, and click OK. Restart your host and client computers, and you'll be ready to share your dial-up connection.

Just remember to disable Internet Connection Sharing and reenable DHCP in the router when your broadband connection is up and running again.