* Reindl Harald <h.rei...@thelounge.net>: > > > Am 25.06.2013 15:28, schrieb Timo Sirainen: > > Also there are several potential problems.. Like if there are duplicate > > Message-ID: headers, > > but the body is different, should that be a duplicate? > > the answer is simply *yes* because there must not be the same > Message-ID's for different messages because the words "single > unique message identifier" are pretty clear > _______________________________________________________ > > RFC2822 > > Though optional, every message SHOULD have a "Message-ID:" field. > Furthermore, reply messages SHOULD have "In-Reply-To:" and > "References:" fields as appropriate, as described below. > > The "Message-ID:" field contains a single unique message identifier. > The "References:" and "In-Reply-To:" field each contain one or more > unique message identifiers, optionally separated by CFWS. > _______________________________________________________ > > these days "every message SHOULD have a Message-ID:" is outdated > > we started many years ago to block *any* message missing the > header because every sane SMTP implementation adds it if it > was missing from the client and so only broken implementations > which are mostly spammers would be affected
We had one funny occurance of that particular corner-case: * Somebody sent us an email * the user's account autoreplied on the eveing upon receipt (out of office) That autoreply was sent with a message-id A * next morning, the user read the mail, and composed a personal reply * that reply was discarded by the recipient's mailserver, since it had the same message-id A (dunno why that happened, but it did!) as the auto-reply the evening before. That took me a while to discover. -- Ralf Hildebrandt Geschäftsbereich IT | Abteilung Netzwerk Charité - Universitätsmedizin Berlin Campus Benjamin Franklin Hindenburgdamm 30 | D-12203 Berlin Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962 ralf.hildebra...@charite.de | http://www.charite.de
