With two or more PCs per household becoming commonplace, Microsoft set out to do families and roommates a favor when it added Internet Connection Sharing (ICS) to Windows. But the feature isn't always a cinch to set up — and sometimes, it isn't really necessary. Let's check this week's Q&A mailbag:
My roommate and I are having problems trying to share an Internet connection, with her system and ADSL modem set up as the host. We bought a Linksys BEFSR41 router and connected the network cable from the modem to the WAN port, then connected both of our PCs to LAN ports on the router. Both computers are running Windows XP — hers Professional, mine Home Edition.
After we connect everything, we try to use the Network Setup Wizard but receive an error message that reads, "Cannot complete the Network Setup Wizard: Other computers cannot connect to the Internet through this computer. In addition to its Internet connection, this computer must have a connection to your network." What gives?
The fact that you describe one Windows XP computer as the "host" system leads me to believe that you're trying to set up the operating system's Internet Connection Sharing feature. Actually, if you have a broadband router like the Linksys BEFSR41, you shouldn't be using ICS at all.
ICS is necessary only when you lack a router and instead link your Internet connection (e.g., your roommate's DSL modem) directly to a PC. To properly configure ICS, you'd need two network adapters in the host PC — one to connect to the broadband modem and the other to connect to your internal network and the machines on it.
When you're using a router, this isn't necessary: You simply connect the computers to the router and the router to the DSL line. The only configuration that needs to take place on the workstations is to verify that the machines' network adapters are configured to obtain an IP address automatically. Attempting to use both a router and ICS together would explain why you received the error message you did.
From checking its specs online, I see that your Linksys router has a built-in 4-port switch, so you can just plug each machine's Ethernet cable into the router. If it doesn't immediately assign your systems IP addresses, it could be because the person who installed your router disabled its DHCP service.
The easiest way to resolve the latter problem is to simply reset the router back to the default factory settings. A reset switch can usually be found on the back of the router. Once this has been done, you should be able to connect to the router via a Web browser, using its default address and logon information (it's probably 192.168.0.1 or something similar). Your router's documentation can provide you with all the information you'll need to accomplish this.
Most of today's routers come with a setup wizard that will configure your router to work properly with your DSL line. Once this is done, you should find that both of your PCs have access to the Internet connection.
