Alas! I discovered what the problem is...my router!
If you have a Linksys BESR41 router...don't use BitTorrent. Or Gnutella as an ultrapeer. Apparently, the firmware on this, and other products that have this chip in common, crash and burn when a large (>16) number of connections per IP address behind NAT are established. In other words. A very busy Torrent will bork your router, and the only way to fix this is to reboot it.
This is one of the reasons why I find old (P/100 type) machines and make them home firewalls with Fedora! <grin>
Fun :-(
More fun when your firewall also does DNS, DHCP, and NTP for the home network. <smile>
-- Rodolfo J. Paiz rpaiz@xxxxxxxxxxxxxx