On Tue, 19 Jun 2012, Jethro R Binks wrote:
> From: Jethro R Binks <jethro.binks@???>
> To: exim-users@???
> Date: Tue, 19 Jun 2012 13:37:08
> Subject: [exim] Delays, timeouts, and conflict
>
> I've been having an ongoing discussion with a supplier about their
> inability to send us email.
>
> Here's a summary of one of the transactions:
...
*Extremely* wild stab in the dark here. Try reducing the MTU on
your mail relay(s) slightly. Say from 1500 to something like 1400
to 1450.
Saw something like what you describe several years ago with getting
email to the NHS. Long delays, timeouts, dropped connections
etc. It was suggested to me that something in the connection
route had broken path MTU discovery. Reducing the MTU was a great
improvement.
--
Dennis Davis, BUCS, University of Bath, Bath, BA2 7AY, UK
D.H.Davis@??? Phone: +44 1225 386101