Mailscanner generated duplicate message

[Glenn Steen]

On 07/02/2008, Cedric Devillers <cde at alunys.com> wrote:
> Hello,
>
> I'm trying to revive this thread from the last month because we are
> observing the exact same behavior on one of our servers.
Thanks for doing that, and for providing some more info.

> So to remember the facts :
>
> - We are using mailscanner with postfix, and duplicated messages are
> generated by mailscanner.
>
> - This system is the only one where we are observing this behavior. It
> have a little particularity : it mainly act as a mail relay, but
> sometimes many mails are generated by the server itself (a script) and
> injected in postfix queues via sendmail command. We can always reproduce
> some duplicated messages with this script.
>
> - MailScanner is configured (by ruleset) to bypass scanning for thoses
> messages, but they are still entering the mailscanner logic (postix ->
> hold queue -> mailscanner (no scan) -> active queue).
What does the ruleset look like? I'm sure it doesn't matter, but ...
just out of curiosity:-)...

> - Mailwatch is running on this server, and for each duplicates we see
> entries with null size body (2, 3, 4, sometimes 5) then at last a final
> entry with the full body. Note that the recipient see the full body on
> every duplicate.
>
> It looks like a locking problem, because all duplicates are with the
> same postfix queue ID and different entropy part (ID.xxxx, ID.yyyy,
> ID.zzzz, etc). Can it be possible that a mailscanner child "fail" to
> lock some queue file when message is marked not to be scanned by
> mailscanner ?
Yes, this seems plausible... Could you provide some log examples? Just
to see that it really is separate children reading the same queue
file...


> I will not be very helpfull to debug perl code, but i can provide any
> needed logs to help finding the origin of the problem.
I'll see what I can do, but... I think this isn't "my" code snippets,
but a thing that might have been present for a while... And I have a
serious lack of time to spend on this ATM (worse than last time,
before Xmas)... So no promises:-).

> This is really a serious problem in this particular installation. But i
> must say that we have dozens of other servers that are running
> mailscanner/postfix, and we are very happy about thems :)
Does it help if you DO scan with MS, but skip things at the next
level, for example:
Scan Messages = yes
Use SpamAssassin = no
Dangerous Content Scanning = no
... and possibly a few more (do them with a ruleset, of course:-)?

Cheers
-- 
-- Glenn
email: glenn < dot > steen < at > gmail < dot > com
work: glenn < dot > steen < at > ap1 < dot > se