airport express and non-apple wifi networks

I have an Airport Express, which I love, but I've had no end of problems trying to get it to join our house wifi network so that I can use AirTunes to stream music to the Bose radio in the family room.

Last night I finally found a page that explains why. It's a post to a discussion forum on the Apple site, entitled How to make the Airport Express work with Windows XP and an existing D-Link router. Now, I don't have XP or a D-Link router, but it turns out the instructions were relevant for my OS X and Linksys (I think...can't remember the brand) router combo.

The basic problem, it seems, is that by default the AirportExpress only wants to join networks using 10.0.x.x DHCP ranges. Many routers, however, use the 192.168.x.x (or 172.16.x.x) range for DHCP. As a result, the AirportExpress could see my home network, but couldn't successfully join it.

The solution is a kludge, but it works. You have to go into the Airport Admin Utility, and start to set up a new wireless network. That allows you then to go into the network settings and tell it to use the appropriate IP range. When you switch it back to joining an existing network, it remembers the IP range. Yes, I know, it's ugly. But it worked!

The instructions I linked to are pretty clear, and work for either OS X or Win XP. But they do have one glaring error--in step 10, they say to unplug the Ethernet cable from the AirportExpress. Don't do it! You can't do step 11 (update the settings) when it's unplugged. (D'oh!) Don't unplug the Ethernet cable until after you've successfully run the settings update.

It worked like a charm for us, and I have good music in the family room again. Yay!

(I should note that when I called Apple tech support about this last month, they told me that the AirportExpress couldn't join a non-Apple network. I'm glad they were wrong.)