i didn't have time to fully debug this situation today, but i noticed that on some hosts, icmp unreachable messages do not terminate the connection, though snoopy did see the icmp packet.
Nor should they. A temporary routing flap is no reason to arbitrarily tear down a viable TCP connection. Instead, tell the application and let it decide what to do.
And don't get me started about SSH and TCP keepalives, or the lack thereof when I shut the lid on my laptop! (No, not the Plan9 ssh.)
--lyndon
