Hi,
> From: Phil Pennock [mailto:exim-users@spodhuis.org]
>
> Internal default values always get exposed as the default value of an
> option and can be interrogated with `exim -bP`.
Yes, thanks for the reminder. Been swearing at Exim for err (counts fingers) 14 years now and the obvious passed me by!
Further investigation at this end has revealed a couple of things:
That a certain MSSQL server which has recently been replaced was not configured to use SMTP quite as sanely as we would like. Ignoring 4XX errors was a good start as it was treating all errors as a 550 error and so not bothering to defer and try again, secondly it was indeed trying to dump as many mails as it could down a single SMTP connection. Apparently (my colleagues tell me) it now handles errors correctly and to use reasonably sized batches.
Fundamentally our internal MXs were doing the right thing, we had recently replaced them, but the smtp_* options were deliberately left the same as previously as we knew they worked.
Thanks
Paul