On Tue, 2012-08-21 at 06:57 -0400, Sam Varshavchik wrote: > Lindsay Haisley writes: > > > Sam, et al, > > > > Here's a situation that happened recently. I posted to a popular > > mailing list and courieresmtp logged the following. > > > > Aug 19 20:12:06 shakti courieresmtp: id=000000000027586D.0000000050318EDD. > > 00006F31,from=<[email protected]>,addr=<[email protected]>: > > 450-4.3.2 Service currently unavailable > > Aug 19 20:12:06 shakti courieresmtp: id=000000000027586D.0000000050318EDD. > > 00006F31,from=<[email protected]>,addr=<[email protected]>: 450 > > > > 4.3.2 Contact your postmaster/admin for assistance. Please provide the > > following information in your problem report: time (A... > > Aug 19 20:12:06 shakti courieresmtp: id=000000000027586D.0000000050318EDD. > > 00006F31,from=<[email protected]>,addr=<mailman- > > [email protected]>,status: deferred > > > > The connecting server at python.org returned a temporary error. > > Apparently Courier queued this email for redelivery, and the MUA > > (Evolution) noted the failure and apparently left the problem email in > > my Outbox. > > Not possible. If Courier already has this message, the MUA must've sent it, > and, as far as the MUA is concerned, the message has been sent to the mail > server. > > A MUA has absolutely no means, whatsoever, to know anything about the > message after it sent it to the mail server. Once Courier receives a > message, it acknowledges it with a 2xx. It does not wait and try to forward > the message, before acknowledging it.
OK, a little work with tcpdump and swaks clarified how things actually work. The designated SMTP server for the MUA engages in _two_ SMTP dialogs, one with them MUA and one with the recipient mail server. Please excuse me. I don't deal enough with relaying to be fully familiar with the way things work. Usually I'm testing the MDA and connect with the MTA on the same box. Is there any possibility that Courier, when relaying, might hold open the connection with a requesting MUA until the connection with the recipient server is complete, and return something to the MUA accordingly? In particular, is there any difference in the behavior of Courier when a recipient server returns a 450 tempfail, as opposed to a 451 code? > > A minute later, the MUA tried again, successfully: > > > > Aug 19 20:13:10 shakti courieresmtp: id=00000000002758BD. > > 0000000050318F21.00006FAC,from=<[email protected]>,addr=<mailman- > > [email protected]>: 250 2.0.0 Ok: queued as 3X0cTL2xBFzQM6 > > Aug 19 20:13:10 shakti courieresmtp: id=00000000002758BD. > > 0000000050318F21.00006FAC,from=<[email protected]>,addr=<mailman- > > [email protected]>,size=4147,success: delivered: mail.python.org > > [82.94.164.166] > > Aug 19 20:13:10 shakti courieresmtp: id=00000000002758BD. > > 0000000050318F21.00006FAC,from=<[email protected]>,addr=<mailman- > > [email protected]>,size=4147,status: success > > This is Courier sending a different message. This is not your MUA. Well I suspect it _was_ the MUA which inserted this since this message was identical in all respects to the previous one, except for the assigned message ID, and the list subscribers received two identical posts from me. The message IDs back this up. I'm very fond of my chosen MUA, Evolution, which is nearly as powerful for mail management as some of the old CLI mail programs such as Mutt. T-bird can't touch it, although with recent improvements it's getting there. Evolution does, however, have "issues", which is probably a good part of the reason it's no longer the default MUA for recent versions of Ubuntu Linux. -- Lindsay Haisley | "Everything works if you let it" FMP Computer Services | 512-259-1190 | --- The Roadie http://www.fmp.com | ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ courier-users mailing list [email protected] Unsubscribe: https://lists.sourceforge.net/lists/listinfo/courier-users
