Am 27.04.2011 00:50, schrieb Joseph Tam:
Robert Schetterer <robert@schetterer.org> writes:
Anyway, why use lmtp over lda ?
i.e avoid backscatter by overquota
A clarification on this: backscatter (or rather, ambiguous NDR notices that claim many users are over quota rather than just one) is a result of a local mailer that support multiple recipient delivery in one invocation, but can only return one result code to the MTA.
Since Dovecot's deliver-lda does not support multiple recipient delivery, this is not a problem.
LMTP can support multiple deliveries of the same message per invocation, but replies with individual SMTP codes to avoid the above problem. It can take advantage of this to efficiently implement single instance storage if it is enabled.
in my understanding lmtp acts more like a mta so overquota "reject" can be send during smtp income stage i.e with postfix, to the sender client
with lda this isnt possible cause the the mta does give the whole mail to lda which and mta send "recieved" to the sender client ( so the bounce must be send later by binary sendmail etc )
whatever this is the behavior i ve tested in my setups, may Timo correct me if i fail here
performance should better too
Apart from multiple deliveries or SIS, I'm not sure this is true, or significant if it were.
yes this should be meassured, youre right i dont know too if its really performance relevant, but multiple deliver is nice to have anyway, why should not use it
Joseph Tam <jtam.home@gmail.com>
however i see no reason to use lda longer in my setups as lmtp exits youre right the backscatter case is really rare anyway
Best Regards
MfG Robert Schetterer
Germany/Munich/Bavaria