I have Ubuntu 10.10 on my Dell laptop. I use wireless broadband internet connection. Until recently, I could download from torrents, but now it shows a lot of peers, while not being able to connect to even one (or sometimes one). Hence, the download speeds are either zero or 1.something KiB/s.

This happens using Transmission. When I checked the ports for various port numbers, it showed them all closed, whereas at the same time, Deluge showed them to be opened.

In Transmission, UPnP or Nat-PnP option is checked, as well as the "pick a random port" one.