Author: Adam D. Barratt Date: To: Stian Jordet CC: exim-users Subject: Re: [exim] Hotmail and 552 Too many recipients
Hi,
Stian Jordet wrote: > I have a user which have a soccer contest going with his friends and
> co-workers. They are now about 60 participants. For a couple of years
> he have been sending out the results and standings to everyone
> participating. This have worked great. [...] > Two questions: 1) is the reason Hotmail now rejected his email that
> it's suddenly 16 hotmail recipients instead of 14? I thought it must
> accept
> at least 100 (although I know Hotmail isn't known to adhere to the
> RFC's...) Perhaps it's because the recipients are in the bcc-field?
> Maybe there is limits there?
>
> 2) Why did only six of the 16 Hotmail recipients fail? Oh, stupid me,
We had exactly this problem recently - the magic threshold appears to be 10
recipients. Delivery to the first nine recipients of a message succeeds, the
tenth and subsequent fail.
The solution I came up with is to set max_rcpt to nine or less on the smtp
transport delivering the mail to Hotmail. You could either do this globally
on your current transport (e.g. remote_smtp) or (as we did) create a copy of
the relevant router which only matches hotmail.{com,co.uk} and configure
that to use a copy of the transport but with max_rcpt set. Obviously the new
router should be placed before the existing one (assuming the current router
has domains=* or similar).