tcp connections dropped in 2.6.7

From: David N. Welton
Date: Tue Jul 13 2004 - 11:47:10 EST


[ Please CC replies to me. Thanks! If there is a more specific list, I will go there. ]

Hello,

This one has really got me stumped, and I would like to debug it if possible (although my boss would really like the machine to 'just work'). I think it's in the kernel because it affects all userspace programs equally.

The problem:

When logged into the machine via ssh, every so often the connection goes down (not frozen, it goes away completely) and attempts to log back in fail. Seemingly, networking comes back up ok if, from the server (the one with the problem) I generate some outgoing traffic - even a single icmp packet. Pings to the machine in question normally run around 0.12 ms from my machine, but slow down to 2 or 3 ms during the problem.

On a suggestion from someone, I tried turning off the windowing bit which has apparently caused some problems lately, but that doesn't help (I'm not going through a router in any case).

There are no messages at all in logfiles. tcpdump doesn't show anything that looks obvious (to me at least... could be me not seeing something).

Seeing as how outgoing traffic seems to kick the connection back into shape, as a crutch I tried leaving a ping running, but it went down just the same.

As a network card, I'm using a realtek. Initially I observed the problem with a forcedeth card, which we substituted thinking that might be the problem.

I don't seem to be able to recreate the problem. It "just happens" every now and then.

I'll put a dmesg up at http://dedasys.com/dmesg.txt

Thankyou for your time,
--
David N. Welton
davidw@xxxxxxxxxxx
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/