On 13 Aug 2003, Andreas M. Kirchwitz wrote:
> I'm connected with ISDN (64 kbit/s), and if the utilization of the
> line is very high, Exim sometimes silently drops incoming connections
> upon connect. No entry to the logfile (mainlog) is made, no SMTP
> response code is given. I don't even get the typical log entry
> "SMTP connection from [1.2.3.4]:4711 (TCP/IP connection count = 1)".
That almost suggests that Exim didn't even receive the connection.
Writing that log message happens pretty early on.
> If Exim drops the connection, it usually happens within the first
> about 5 seconds after the connection has been initiated from the
> outside world (Internet).
I think the first thing to try to find out is whether it is Exim, or
your OS, that is dropping the connection (3-way TCP handshake not
completing in time?). But I don't know how to do this. Maybe tcpdump
could help.
> However, once the SMTP connection has been established, Exim won't
> drop the connection (even on high bandwidth load).
Again, that suggests Exim isn't actually getting the connection in the
problem cases.
--
Philip Hazel University of Cambridge Computing Service,
ph10@??? Cambridge, England. Phone: +44 1223 334714.
Get the Exim 4 book: http://www.uit.co.uk/exim-book
