From maine@altair.dfrf.nasa.gov Sat Sep 26 00:45:34 1992 Received: from altair.dfrf.nasa.gov by dkuug.dk via EUnet with SMTP (5.64+/8+bit/IDA-1.2.8) id AA14734; Sat, 26 Sep 92 00:45:34 +0200 Received: by altair.dfrf.nasa.gov (4.1/SMI-4.1) id AA13049; Fri, 25 Sep 92 15:45:30 PDT Date: Fri, 25 Sep 92 15:45:30 PDT From: maine@altair.dfrf.nasa.gov (Richard Maine) Message-Id: <9209252245.AA13049@altair.dfrf.nasa.gov> To: SC22WG5@dkuug.dk In-Reply-To: Jerrold L. Wagener's message of Wed, 16 Sep 92 09:19:53 CDT <9209161419.AA12320@trc.amoco.com> Subject: (SC22WG5.212) are there any email Message-Id standards? X-Charset: ASCII X-Char-Esc: 29 On Wed, 16 Sep 92 09:19:53 CDT, Jerrold L. Wagener said: Jerrold> Below is a list of the Message-Id's of a sampling of email Jerrold> messages I have recently received. Though there is some Jerrold> commonality, it appears that each network has its own form of Jerrold> Message-Id, and I can't tell if there's some underlying Jerrold> standard or not. Does anyone know of any work on email Jerrold> message id standards? Sorry to be so slow in replying. I had this on my list of pending things to dig up, but I figured somebody else would probably have beat me to it long before now. If they did, it must have been in private e-mail to Jerry. The relevant standard is RFC 822, "Standard for the Format of ARPA Internet Text Messages," dated August 13, 1982. I can send a complete electronic copy of the standard to anyone that wants, but it is about 3000 lines long so I don't think I'll post the whole thing here. Some relevant extracts follow. ---------------- msg-id = "<" addr-spec ">" ; Unique message id addr-spec = local-part "@" domain ; global address local-part = word *("." word) ; uninterpreted ; case-preserved domain = sub-domain *("." sub-domain) sub-domain = domain-ref / domain-literal domain-ref = atom ; symbolic reference ---------------- There is more detailed BNF defining the lower level constructs like "word" and "atom", but I'll omit that from this extract. ---------------- 4.6.1. MESSAGE-ID / RESENT-MESSAGE-ID This field contains a unique identifier (the local-part address unit) which refers to THIS version of THIS message. The uniqueness of the message identifier is guaranteed by the host which generates it. This identifier is intended to be machine readable and not necessarily meaningful to humans. A message identifier pertains to exactly one instantiation of a particular message; subsequent revisions to the message should each receive new message identifiers. ---------------- This is pretty much all that the standard says about the message ids (except for the lower level syntax details). As you can see, there is not much specification of the "local-part" except the requirement that it uniquely identify the message and fit within the syntax constraints. The "AA" field Jerry noticed is probably just part of a "counter" of some kind used by local mailers to generate unique ids. By the way, I think that one of Jerry's listed message ids, Jerrold> violates the standard because of the spaces around the "@". There is some stuff about where spaces are allowed in part of the low level syntax that I didn't quote, but I didn't study it carefully enough to be sure. -- Richard Maine maine@altair.dfrf.nasa.gov