Am 14.01.2015 um 02:23 schrieb Robert Blayzor:
On Jan 13, 2015, at 7:34 PM, Reindl Harald h.reindl@thelounge.net wrote:
and what would that change? nothing if you think about how mail works!
- the MTA receives the message
- the MTA confirms with 2xx status code
- later the delivery server rejects
- the MTA *must* create a bounce
just don't reject mails after you confirmed you have received them in the SMTP session and if you don't want a mail after that DISCARD it by consider legal implications - there is nothing between
The above is not entirely true. You are assuming that your MTA it's sending a 2xx accepting the message immediately before delivery via LMTP completes. With PRDR (in Exim for example, or without) a 5xx during the LMTP transport should issue a 5xx error back to the sending MTA, not a 2xx. Therefore, there would be no NDR generated by the receiving system. The senders MTA would have to generate the NDR, but that's not my problem at that point. Of course WITHOUT PRDR this is a little bit more of an issue since it would be a rejection for all recipients of the message.
i assume a sane MTA like postfix with a queue and so be able to receive and confirm messages independent of the final destination - even if you use typically LMTP there could be an external transport for a RCPT and the same message can have internal and external destinations
so what you want in your OP is just DISCARD in a sieve script and there is no point in "Using Dovecot LMTP it would be more optimal to kick a 5xx back" when the desired result is DISCARD
why do you want the burden of keep the SMTP session with the client open until the mail is finally stored? that don't scale!