Bwana asked, so here's a spew of techno-babble about configuring the Airport networking stuff:
Getting back to the Airport discussion, I found a couple of major problems.
1) The Airport Express needed the Airport Extreme base station set up in a very specific fashion in order to extend the range of the network. This wasn't particularly documented anywhere I could find.
2) If the Airport Express (and to a lesser degree the Extreme) gets borked up, it's not really fixable without resetting the entire unit. Basically the UI for configuring it relies on wireless communication. If you program it to not be functional, it will reboot and the the UI can't connect to it anymore.
In more detail this is what happened.
1) I unplugged my 802.11b wireless access point, thus shutting down the Jesternet wireless LAN.
2) I plugged in the Airport Extreme and booted it up. I ran the Airport Setup Assistant to configure it. So far so good.
3) I decided to use the WPA security - that's the best option the Extreme offers. This was the first issue - Airport Express won't support extending WPA. This might be obvious to an expert - it wasn't clear to me.
4) I turned off the ability to provide IP addresses - I wanted those to come from the router/DHCP server on the wired LAN. This was the second issue - it's going to prevent successful setup of the Express later.
5) Got the Extreme working, got both Powerbooks talking to it via WPA. Woot! It's fast, it's good.
6) Plugged in the Airport Express. It comes online, my Powerbook can see Jesternet (via the Extreme) and Apple network whatever (via the Express). Of course, the Express isn't talking to the Extreme, so it doesn't really have internet. But we'll configure that.
7) Run the Airport Express Assistant. Tell it I want to have it connect to an existing wireless network. Whoops, the Express won't use WPA. OK, well, let's change the Extreme back to WEP. Cancelling out of the AirPort Express setup reboots it partially configured and it goes offline. Hard reset it with a ballpoint pen. (Did I mention it was up on top of the TV in an awkward place for poking at?)
8) Go to reconfigure Extreme. Knock it down to WEP. Reconfigure both Powerbooks to talk to it via WEP.
9) OK, JesterNet is back as a WEP network, and Apple_Network_xxxx is back online. Let's configure the Airport Express. Now it won't extend the network due to the fact that the Extreme isn't serving addresses (which it really shouldn't). Cancel that, we're back at the pen and power-cycle routine.
10) Let's try bringing the Express up as a NEW network to see what happens. Go through that process. Woot! That works. I can name it, I can stream iTunes to it. But I have to decide whether I want to join the "Living Room" network, which has iTunes streaming but no internet, or "Jesternet" with internet but no streaming. Yuck.
11) OK, let's try letting the Extreme hand out some IP addresses. You can't use the Assistant for that, you have to use the AirPort Admin Utility. Wheee. Turn on the check box, and hit OK. Wait - does that say it's going to use 172.xxx.xxx subnet? That won't work with rest of my LAN. Change it to 192.168.1.x and hit OK. Wait, did it say it's OWN IP address would be 192.168.1.1? That's an address conflict.
12) So the Extreme just rebooted and dropped off the network. Yarrgh. In order to fix *THAT*, I had to take the Extreme off the wired LAN, power cycle it, and have the Mac connect wirelessly to "192.168.1.1", change it's address to a good one for my LAN, reboot the Extreme and plug it back into the LAN.
13) OK, back to the AirPort Extreme. OK, somewhere along the line it got screwed up again, needed the pen-and-power cycle trick.
14) There were a few more go-rounds of this nature that I don't remember the full details of. Basically if you misconfigure an Airport Extreme it's gone, and you have to hard-reset it. And there isn't any simple documentation that says what settings your Extreme needs before the Express can extend the range of the network.
Getting back to the Airport discussion, I found a couple of major problems.
1) The Airport Express needed the Airport Extreme base station set up in a very specific fashion in order to extend the range of the network. This wasn't particularly documented anywhere I could find.
2) If the Airport Express (and to a lesser degree the Extreme) gets borked up, it's not really fixable without resetting the entire unit. Basically the UI for configuring it relies on wireless communication. If you program it to not be functional, it will reboot and the the UI can't connect to it anymore.
In more detail this is what happened.
1) I unplugged my 802.11b wireless access point, thus shutting down the Jesternet wireless LAN.
2) I plugged in the Airport Extreme and booted it up. I ran the Airport Setup Assistant to configure it. So far so good.
3) I decided to use the WPA security - that's the best option the Extreme offers. This was the first issue - Airport Express won't support extending WPA. This might be obvious to an expert - it wasn't clear to me.
4) I turned off the ability to provide IP addresses - I wanted those to come from the router/DHCP server on the wired LAN. This was the second issue - it's going to prevent successful setup of the Express later.
5) Got the Extreme working, got both Powerbooks talking to it via WPA. Woot! It's fast, it's good.
6) Plugged in the Airport Express. It comes online, my Powerbook can see Jesternet (via the Extreme) and Apple network whatever (via the Express). Of course, the Express isn't talking to the Extreme, so it doesn't really have internet. But we'll configure that.
7) Run the Airport Express Assistant. Tell it I want to have it connect to an existing wireless network. Whoops, the Express won't use WPA. OK, well, let's change the Extreme back to WEP. Cancelling out of the AirPort Express setup reboots it partially configured and it goes offline.
8) Go to reconfigure Extreme. Knock it down to WEP. Reconfigure both Powerbooks to talk to it via WEP.
9) OK, JesterNet is back as a WEP network, and Apple_Network_xxxx is back online. Let's configure the Airport Express. Now it won't extend the network due to the fact that the Extreme isn't serving addresses (which it really shouldn't). Cancel that, we're back at the pen and power-cycle routine.
10) Let's try bringing the Express up as a NEW network to see what happens. Go through that process. Woot! That works. I can name it, I can stream iTunes to it. But I have to decide whether I want to join the "Living Room" network, which has iTunes streaming but no internet, or "Jesternet" with internet but no streaming. Yuck.
11) OK, let's try letting the Extreme hand out some IP addresses. You can't use the Assistant for that, you have to use the AirPort Admin Utility. Wheee. Turn on the check box, and hit OK. Wait - does that say it's going to use 172.xxx.xxx subnet? That won't work with rest of my LAN. Change it to 192.168.1.x and hit OK. Wait, did it say it's OWN IP address would be 192.168.1.1? That's an address conflict.
12) So the Extreme just rebooted and dropped off the network. Yarrgh. In order to fix *THAT*, I had to take the Extreme off the wired LAN, power cycle it, and have the Mac connect wirelessly to "192.168.1.1", change it's address to a good one for my LAN, reboot the Extreme and plug it back into the LAN.
13) OK, back to the AirPort Extreme. OK, somewhere along the line it got screwed up again, needed the pen-and-power cycle trick.
14) There were a few more go-rounds of this nature that I don't remember the full details of. Basically if you misconfigure an Airport Extreme it's gone, and you have to hard-reset it. And there isn't any simple documentation that says what settings your Extreme needs before the Express can extend the range of the network.