Sometimes trackers go down. It'll be hard to get a connection, but you'll be able to see it if you look at the details of that particular torrent.
Make sure uPNP is turned on, or your ports are forwarded correctly, then try like j_maddison says, and give the nat test a shot. You should be good there.
If you're really looking for "speed boost", and not actually talking about 0 kb/s, then you might be dealing with a crappy firewall. I had an old Asante firewall that finally gave up the ghost. Because I use VOIP, I shopped around and went looking for a QOS router, settling on the DGL 4100. Using that box is like night and day. Suddenly, pings to my local firewall are .1ms, instead of 2-3 ms. Torrent throughput to the outside world went up 50%, and torrents can coexist with VOIP without interruption or quality degradation. With my old Asante, I couldn't upload a torrent more than 30KBps. With this D-Link, I can saturate my connection at 50KBps -- and it barely goes down when I place a Vonage call (which sounds as good as Vonage ever does).
