[Mailman-Users] Some subscribers receiving multiple copies

[Nigel Metheringham]

I previously wrote:-
> will at connectcorp.net said:
> > Some of our subscribers are reporting receiving 2, 3, or even 4 copies
> > of each post. 
> 
> I've seen very occasional examples of this on our list running mailman 
> 1.0.  The headers show that the duplication is occurring at the point 
> where mailman injects the message into the MTA for delivery to the list 
> subscribers.

...

> The injects were spread over a 5 or so minute period, with the last 2 
> (duplicated) injects done 2.5 minutes apart.  The machine would have 
> been quite heavily loaded around that time - there was a message still 
> in the process of injection by mailman when the second arrived and a 
> few messages in the mailq.

It appears this happens at times of high load and/or when the DNS is 
not very available.  Suspicions are that mailman is retrying a 
submission that it thinks is timing out.

In an attempt to work round this I have stopped exim doing receipient 
address verification on the fly for incoming messages from mailman (the 
config line is
	receiver_verify_hosts = !127.0.0.1/8:0.0.0.0/0
).

This, so far (one day), appears to have fixed the problem.  However its 
early days yet.

	Nigel.
-- 
[ Nigel Metheringham                  Nigel.Metheringham at VData.co.uk ]
[ Phone: +44 1423 850000                         Fax +44 1423 858866 ]