I've noticed occasional (maybe every half hour) odd messages in my router firewall logs:
PORT SCANNER ATTACK detected from ip address. Source port is port, and destination port is my port which use the TCP protocol.
the bits in italics above change from message to message apart from my port which is always the Transmission port (manually forwarded).
Anyone well up enough on routers (mine's a Belkin with latest firmware) to know what would trigger a "Port Scanner Attack" response? This generally doesn't appear to be stopping torrents from up/down loading but might explain why some peers don't seem to last long.