Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!rutgers!njin!uupsi!sunic!nuug!ifi!enag From: enag@ifi.uio.no (Erik Naggum) Newsgroups: comp.mail.sendmail Subject: Re: Mail addresses and RFC1123 Message-ID: Date: 30 Jul 90 20:33:48 GMT References: <9007242101.AA32438@cs.niu.edu> Sender: enag@ifi.uio.no (Erik Naggum) Organization: Naggum Software, Oslo, Norway Lines: 80 In-Reply-To: fitz@wang.com's message of 27 Jul 90 22:20:38 GMT Originator: enag@slembe.ifi.uio.no Nntp-Posting-Host: slembe.ifi.uio.no Lines: Hope I'm not late with this, it's been sitting in its own emacs buffer after I accidentally renamed it. Such is life with powerful tools. In article I wrote: >> I was there when RFC1123 was written. I had my own misgivings about >> the language and use of parentheses with respect to the "routig >> operators". However, Bob Braden (the editor) told me what he had in >> mind, and I saw that it was good. In article fitz@wang.com (Tom Fitzgerald) replied: > May I ask why? It causes problems for UUCP sites, and basically forces > us to rewrite the local parts of nonlocal addresses (turning a%b into b!a) > in order to get stuff delivered. (We don't do the rewriting here, so > we suffer with a fair amount of undeliverable mail). Taken as a whole, RFC 1123 improves the chances for mail to get from A to B. Several important items: It clearly states that you must not touch or interpret a local-part unless you're [responsible for] the receiving domain. Second, it clearly states that source routes are Bad. It also specifies one way to do what I call "subaddress" mail with the "%-hack". (The distinction between source route and subaddressing is implicit in the HRRFC, but I've found a need to make the distinction explicit, and chose this name for it.) Note: This is only one way to do it, a suggested way, but you don't have to abide by this, since we took great pains to ensure that only the target host interpret the local-part. I would recommend following it for interoperability reasons on the Internet proper, though. RFC 822 and the HRRFC has very little to say on local-parts. We don't say that you should only use the %-hack. The 5.2.16 discussion paragraphs even include an example with a bang-path local-part. >> The Internet is not, as I have had to point out to several people, >> a conglomeration of networks and standards of all sorts, it's one >> particular technology with one particular standard protocol suite. >> SMTP and RFC822 in this case. It has been a tremendous success, >> and other people try to mimick the Internet as best they can. > One of the reasons it has been so enormously successful is its ability > to encompass other networks into it. When two networks merge, the > users adopt the conventions of the more flexible net, and the less > flexible net becomes a special case. So far, the Internet (especially > the DNS) has blown everyone away with its distributed naming authority > and open-ended mail addressing. I agree with this, and I don't think the HRRFC did anything to destroy the open-ended mail addressing in the Internet. Au contraire! > This kind of thing, which makes the Internet more rigid, and less able to > engulf the conventions of other nets, damages some of the things that made > the Internet (especially RFC 822) so successful in the first place. Read the discussions involved, please. It has not been made more "rigid" in any sense. We can still engulf absolutely anything in the local-part, but it would help if certain things are more predictable than others. Always having to check with the receiving domain what it does won't work the way we want, either. Therefore, it was felt that it would be useful to suggest this particular syntax. I think that was very wise. For most applications, it won't matter, as they don't use more than one "sub-routing" character, anyhow. For those who need to source-route for testing purposes, it's very convenient to know what will work. For the sub-addressing question, it's clearly a local problem, but again uniformity is a bonus. I think we should try to refer to source routing as an intra-net (be it the Internet or other) phenomenon, while subadressing is an inter-net (between two nets, one of them perhaps being the Internet) phenomenon. This could help us get a clearer picture of what we're talking about. > I don't care about source routing, but I'd be interested to see the > discussion on the % hack. Could you post it? I'm sorry, but I have a few problems locating it. Give me a few more hours by the tape drive. As I remember, it was a large number of messages devoted to the problem. -- [Erik Naggum] Gaustadalleen 21 +47-256-7822 N-0371 OSLO; NORWAY +47-260-4427 (fax)