Bigpond don't shape or block p2p. The obvious thing that comes to mind is your wireless device. All wireless devices have internal NAT firewalls which is probably why you can't connect. To say you looked around but couldn't find an answer is a little funny. Since at the top of this forum section is a sticky with instructions on how to either enable UPnP or else, forward a port which "is" what you need to do. Connection problems? Check here first! (click on link)

Without further details I can't help any more.