On Thu, 13 Nov 2014, Heiko Schlittermann wrote:
> From: Heiko Schlittermann <hs@???>
> To: exim-users@???
> Date: Thu, 13 Nov 2014 12:33:00
> Subject: Re: [exim] (110): Connection timed out
...
> Wilde guesses, none of these may be sufficient, it's just to explore and
> investigate the behaviour…
>
> - tls
> - ident callbacks
> - different user (telnet you're using as root, exim is running as an
> unpriviliged user)
Another wild guess would be possibly that the MTU value is too high
and hasn't been auto-negotiated down.
A few years ago the organisation I worked for had problems sending
email to a large UK organisation, the NHS. I vaguely remember
discussing the issue on this mailing list.
Turned out that reducing the MTU value of our outgoing mail host(s)
was a solution. Can't remember the exact details, but I think we
dropped the MTU from 1500 to 1400.
Doesn't explain how telnet connections work but exim connections
don't. Unless the test telnet connections are only using "small"
packets.
--
Dennis Davis <dennisdavis@???>
