Bill McGonigle reports a problem - and solution - for a problem that cropped up after applying the AirPort 3.3.1 updater o a typical Airport Extreme setup hooked to a Verizon DSL line.
"After applying the Airport 3.3.1 update the base station was down and non-responsive. A simple power cycle took care of that, but there was no internet connection for the ethernet-connected Mac (B&W G3, 10.3.2). The Airport Admin Utility worked OK (settings were fine) so the Ethernet connection was OK."
"Turns out the Mac was now getting an IPv6 address from the Base Station and apparently the Base Station's NAT doesn't handle that situation properly (in this case the Base Station gets an IPv4 address via a PPPoE link).
"Simply setting the [Configure IPv6] dialog to "Off" on the Network Control Panel's "Built-in Ethernet" screen allowed the Mac to negotiate an IPv4 address via DHCP from the Base Station and then everything worked great, as before."