Creating a Wireless Connection Without a Router

I've done a spate of Wi-Fi oriented posts recently, and a few readers have asked how they can get their computers to talk to each other without a router. It's called ad hoc networking, and here's how to set it up.

But first, a caveat: I do not recommend you use ad hoc networking for more than the occasional file transfer, and even that is better done with a real "infrastructure" wireless network. Ad hoc networking is less secure, buggy, and just not very robust. Getting it to work well can sometimes be a real chore, especially if your two computers don't have the same OS or have different levels of Windows patches. Also, these instructions are only valid if you're using Windows XP with Service Pack 2 to manage your network. If you're running, say, Linksys's proprietary management system on one of the machines, forget about it.

With that said, here's how to set up an ad hoc network:

• Make sure both computers have wireless cards installed and enabled.
• On your first machine, double-click the wireless icon in the system tray, then click View Wireless Networks. On the left, click "Change advanced settings."
• Click the Wireless Networks tab then click Advanced. (We're getting awfully advanced here, if you hadn't noticed.) Here, select the option "Computer-to-computer (ad hoc) networks only" and make sure there is not a check mark in the box at the bottom of that window. Click Close. (Note: This entire step is optional, but if you only want to connect to the ad hoc network you're making, it will make your life easier.)
• This takes us back to the previous menu. Click Add, then type a name for your new ad hoc network where noted. Now, most importantly: Make sure there's a check mark in the box that reads "This is a computer-to-computer (ad hoc) network; wireless access points are not used." (I'll also assume we're leaving encryption off for now. You can turn it on later by returning to this screen and creating a WEP key or WPA password.)
• Now, click the Advanced tab on this menu. Put a check mark next to the option "Allow other network users to connect through this computer's Internet connection."

Believe it or not, we're about done, at least with the first computer. Follow the same instructions for your second computer except for the last one (connection sharing). If you've done everything perfectly your computers should now see each other in the View Wireless Networks screen. If you haven't, try again. Disabling the Windows Firewall is also a big help here, though you're exposing yourself to security risks.

Again I'll note: ad hoc networking is difficult to set up and I've just never had much luck getting it to work very well, so unless you're dedicated, it's probably not worth the bother.

My instructions are about as detailed as I can cram into this blog page, but if you get stuck, here are some other links to people with more detailed instructions on doing the same thing. Note that some of these are dated, and menus have changed a bit over the years.

Good luck!

• Microsoft's official instructions (4 years old but has pictures)
• Micro2000's instructions (more recent, no pictures)
• PC World's instructions (also 4 years old, but exhaustive)