I use a torrent program called Azureus to download things every so often and whenever I do I get the following problem:
It downloads things fine for about the first hour or so but after that I get a message saying something like "make sure port ____ is open" and my downloads stop running.
I use Incoming TCP Listen Port 49152 for Azureus downloads. Azureus has an inbuilt "NAT/Firewall Test" and normally when I type in 49152 and click test it comes back as 'OK'. If I test it again after my downloads have stopped running I get the message 'NAT Error'.
This Azureus problem also causes the rest of my Internet to stop working for some reason and in order to get everything back to normal I have to turn my router off & back on again.
This is pretty frustrating because if I want to leave a download running over night I almost always wake up to find that it stopped downloading about an hour after I went to bed.