Update: There’s a happy end to the story. My dad managed to get hold of a BT Voyager 2100 ADSL router. For some reason it didn’t pick up the DNS settings; however, once I helped him configure DNS on his Mac, everything worked. In particular, iChat AV worked fine for video chat, with no configuration needed on the router.
So: if you’re looking for a good Mac-compatible router to use with BT ADSL, a Voyager 2100 will probably float your boat.
And it was extremely cool to video chat with my parents. Most of the rest of the family live in Bournemouth too, so I’ll doubtless get to talk to them as well over the next few weeks.
Update 2: Someone else with a Netopia wrote to tell me that he eventually got it to work, via the following steps:
I switched off uPnP on the router (iChat loading actually caused the router to crash/reboot with uPnP enabled!).
I switched the firewall setting to “Low” (although “Off” works, as well)
I’m not positive it was necessary, but I also upgraded the router firmware to 7.5 (from the Netopia site).
I left in place the various iChat port-forwarding settings.
Check his site for more info.
We got the parents online from the Mac, but their router doesn’t seem to want to do the port forwarding thing, even when configured to do so. (With the Mac configured as DMZ, I still can’t ping them.)
The router that doesn’t work is a Netopia 3347NWG-VGx, in case anyone out there is considering buying one and finds this page.