There is smtp_accept_max_per_connection which defaults to 1000
'The value of this option limits the number of MAIL commands that Exim is
prepared to accept over a single SMTP connection, whether or not each command
results in the transfer of a message. After the limit is reached, a 421
response is given to subsequent MAIL commands. This limit is a safety
precaution against a client that goes mad (incidents of this type have been
seen).'
Does the reject log show it as a 4xx error or a 5xx one?
The smtp_accept_queue_* options only control whether exim queues incoming messages rather than try immediate delivery - these won't stop reception at all so I think you need to look at the smtp_accept_max options
Jonathan
--
----------------------------------------------------------------------
Jonathan Haynes
Senior Network Specialist
IT Department, Tel: Bedford (01234) 754205
Bld 63, Bedford (01234) 750111 Extn 4205
Cranfield University Fax: Bedford (01234) 751814
Wharley End,
Cranfield, e-mail: J.Haynes@???
Beds, MK43 0AL.
> -----Original Message-----
> From: exim-users-bounces+j.haynes=cranfield.ac.uk@???
> [mailto:exim-users-bounces+j.haynes=cranfield.ac.uk@exim.org] On
> Behalf Of Osborne, Paul (paul.osborne@???)
> Sent: 24 January 2013 09:29
> To: 'exim-users@???'
> Subject: [exim] smtp_accept_* options
>
> Morning,
>
> I have just come across a slighty odd instance where a local server is
> legitimately trying to send out large quantities of mail (12K at a time)
> and my internal MX is unimpressed, dropping the connection with "too
> many messages in one connection" in the rejectlog after around 6K of
> messages.
>
> Now the bit that confuses me here is that I have left:
> smtp_accept_queue_per_connection as the default (this is not in the
> config file at all), so by my reckoning and according to Philip Hazel's
> book "a single SMTP reception process can receive any number of
> messages". I cannot see anything in the online documentation about
> why the connection is being dropped or what any default value now is.
>
> Is there some internal default limit that is being triggered here to cause
> the connection to drop?
>
> I have to admit that the internal sending server appears to have
> changed its behaviour in that previously it would send the mails one at
> a time over individual connections over a relatively long period of time
> where now it seems to be trying one connection and sending the
> whole lot. I guess the theory is that 'they' can say 'the messages have
> been sent in 5 mins' rather than 'yes the messages are being sent now
> and may take a while'. Either way makes no difference to me as they
> are still subject to AV checking.
>
> In addition we have updated Exim in the last few months from
> something so old I cannot recall the version to a more recent 4.72
> (Debian package) - however the smpt_accept_* parameters are set
> the same and I would expect behaviour to be the same.
>
> We have set:
> smtp_accept_max = 150
> smtp_accept_reserve = 50
> smtp_reserve_hosts = +relay_from_hosts
>
> relay_from_hosts are trusted server networks etc (where the
> originating server is based).
>
> I can set smtp_accept_queue_per_connection to a suitably large
> number - but that leaves the question: should I need to?
>
> Thanks
>
> Paul
>
> Paul Osborne
> Systems Analyst
> Infrastructure Group
> Computing Services
> Canterbury Christ Church University
> Tel: +44 1227 782751
>
>
>
>
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