Re: [Exim] "421 too many recipients" got from other MTAs

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Author: Enrico Zini
Date:  
To: exim-users
Subject: Re: [Exim] "421 too many recipients" got from other MTAs
On Tue, Mar 26, 2002 at 09:09:40AM +0000, Philip Hazel wrote:

> then the server has accepted some recipients, and rejected others. Exim
> will try later with the remaining recipients, so the message will
> eventualy get through. On the other hand, if the server is accepting all
> the recipients and then giving the 421 to DATA, the retry will again
> offer all the recipients.


Some hosts were complaining at REPLY TOs, some at DATAs. Anyway, now
I stuck to 100 messages as you said and tomorrow morning I'm confident
I'll see the problem solved.


> > I generate the message body, and then send it multiple times via SMTP to
> > exim giving 2000 different recipients per send. I don't touch the
> > message body between sends, so the message-id is identical. Do I need
> > to change it instead?
> No, I don't think so, but I am not an expert on message-id header lines.


Is there somebody with some more precise idea about it? I fear the
possibility that some funky remote MTA will filter the message as a
duplicate even if the recipient set is different. I know this would be
stupid, but common sense don't always apply...


> I would stick to 100 recipients, sorted by domain, and use a scheme for
> feeding the messages to Exim gently. There was a thread about this on
> the mailing list a few months ago.


I searched for about an hour and the only thing I found was a message
of january, 7 2002 mentioning a thread about towards the end of 2001
that I was not able to find. Unlucky me... Anyway, I feed messages
using two SMTP connections (they are two to make my life easier for
message generation, not for perfomance reasons) from a different machine
connected using a dedicated 100Mbps ethernet cross cable, and I tweaked
the default Debian configuration in this way:

split_spool_directory
auto_thaw = 1h
timeout_frozen_after = 4h
smtp_accept_max = 40
smtp_accept_queue = 5
smtp_accept_queue_per_connection = 5
smtp_connect_backlog = 50
queue_only_load = 2
queue_smtp_domains = *
queue_run_max = 20
remote_max_parallel = 1
# Avoid auth/ident requests towards the press review sender
rfc1413_hosts = ! 10.0.0.0/8 : ! 127.0.0.1/32

Exim is run with -q2m and all of this seems to keep things quiet and
efficient: this morning, 109 messages with 1000 recipients each were
accepted by exim in about 90 seconds, and the majority of the messages
did not spend more than 15 minutes in the queue.

In fact, all the people here are really impressed by the performance of
the new mailing system :)


Thanks a lot for your work and your help! Enrico

--
GPG key: 1024D/797EBFAB 2000-12-05 Enrico Zini <enrico@???>