Re: irc/ircd loopback problem -- Further details

Alan Cox (
Fri, 15 Mar 1996 11:24:14 +0000 (GMT)

> Since the error does not affect ircd->irc_client data flow but
> only blocks irc_client->ircd flow, I would suspect it is the receive
> buffer size change that is killing it. Perhaps some new code incorrectly
> assumes the buffer size to be something other than what ircd changes it to.
> I'll continue investigating.

It breaks if the mtu of the path exceeds the buffer size (near enough). I
don't know why yet, but thats definitely the problem. At the moment Im
still trying to find why 1.3.73+ seem to be losing interrupts or doing
other strange things that break SMP with that problem. The quick cure
for ircd is

ifconfig lo mtu 1500