[Dovecot] deliver saving mails with hard linking

Steffen Kaiser skdovecot at smail.inf.fh-bonn-rhein-sieg.de
Mon Jun 2 14:59:03 EEST 2008

Hash: SHA1

On Mon, 2 Jun 2008, Timo Sirainen wrote:

> I also thought about this, but is it ever useful? Isn't the Received: 
> always different for different deliveries?

In sendmail the Recieved header is added when the mail comes in. Then it
is locally delivered, regardless if directly or from queue.
When two mails with the same content, but different headers come in, a
server cannot (or should not) consider the mails the same anyway, IMHO,
otherwise the admin looses the possibility the backtrack the mail.

So the server is to stick to deliveries with more than one recipients.
Therefore I mentioned LMTP in last mail. Well, just rememebered something: 
When the first delivery attempt tempfailed, e.g. because of out-of-quota, 
and the delivery is attempted next time, LMTP won't help to link the 
previously delivered mail.

This would be different, if headers and body would be storred separately,
but not in Maildir.


> BTW. This also could be done by the wrapper script if really needed.

Yeah, though that is a "wrapper" script ;) which slows down processing and
increases server load.

Actually, I think, there are maintainance usages of "deliver -p", so if
the SHA-1 algorithm is present, it would be good to have "-p", too. :)

Yet something else that (slightly) opposes the SHA-1 variant: If the mail 
has exactly one local recipient, there is no need to do the SHA-1 hashing. 
Different MTAs have different detection methods for this case, I guess. 
E.g. sendmail does not add "(for XYZ)" in the Recieved header. Here LMTP 
would help - or the performance decreasing wrapper :(


- -- 
Steffen Kaiser
Version: GnuPG v1.4.6 (GNU/Linux)


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