There's apparently a bug in either Time Capsule or the 7.3.1 firmware. The DMZ is not working properly. It does not actually allow ALL traffic like it's supposed to. I've seen posts elsewhere on the internet of people having problems with VPN and the 7.3.1 firmware. I've encountered this problem with my video phone, which requires several ports to be open. With it being set as the default host, I can connect to the internet, but certain features are blocked. I've not seen any discussion of this on those forums, so I thought I would bring it up. I've called Apple, and they can come up with no solution. I think it is likely a bug in the firmware, and hope they will fix this as soon as possible.