Networking gets extremely laggy after a random amount of time.

["Maciej Sołtysiak" <solt@dns.toxicfilms.tv>]

Hi,

I have been writing about this problem several times, always without
receiving any pointers on how to approach this.

Networking gets extremely laggy after a random amount of time.
Sometimes it is 5 minutes, sometimes 30hours, sometimes 5 days.

By laggy, I mean that each connection that is established from or to
the linux box (even on the same LAN) is very slow and jitters.
SSH and telnet sessions jitter. When I press a key for a few seconds
it writes in batches, like:
eeee e ee ee eeeeeee e ee

Other streams like http, smtp are very slow.

The only thing that fixes this is to do a /etc/init.d/networking restart

It has been happening on Debian woody and sarge with kernels
from 2.4.16 (the earliest tested) to 2.4.23-rc4 and even on each
2.6 kernel I tried on that box.

The machine is not loaded, and connections I make that are
on localhost device are ok, when these conditions are on.

It propably is NIC related, but I do not know how to investigate
this. I have two 3com 3c905c-tx NICs. One of them is connected
to the LAN, and the other is connected to a hub and is sometimes
used to listen in promiscous mode to investigate traffic.

I would appreciate any pointers on where to look for problems.

Best regards,
Maciej