Path: koobera.math.uic.edu!not-for-mail From: djb@koobera.math.uic.edu (D. J. Bernstein) Message-ID: <1997Oct720.35.30.3223@koobera.math.uic.edu> Date: 7 Oct 1997 20:35:30 GMT Newsgroups: comp.mail.mime Subject: Re: MIME and "Allow 8-bit" in Netscape Nav. 3.01 References: <199710062159.RAA17422@spot.cs.utk.edu> Organization: IR Kari E. Hurtta wrote: > moore@cs.utk.edu (Keith Moore) writes: > > In hindsight, I'm sure we could have done better, but at the time, > > nobody really knew how things would unfold. > Yes, afterward there is always people who know how to do it better. People have been saying for fifteen years that the 7-bit restriction in SMTP should be dropped and that 7-bit mailers should be thrown away. When Q-P was proposed, people pointed out that 8-bit transfer was much easier to implement and deploy, and already successful in the real world, despite requiring support from every link. It's amusing to look back at the conceptual errors that led to the Q-P/8BITMIME mess: * Q-P proponents characterized 8-bit SMTP as ``incompatible''---while they ignored the fact that Q-P was incompatible with existing MUAs. * Q-P proponents claimed that 8-bit SMTP would never succeed, at least not before the Internet's transition to ISO---while they ignored the cost of making Q-P succeed. * Q-P/8BITMIME proponents imagined themselves building a network of ``safe'' 8-bit transfers, with guaranteed Q-P conversion at the boundary---while they ignored the fact that people were already deliberately violating the ``safe'' rules. The situation now is as follows: * Practically every modern MTA accepts unlabelled 8-bit messages and does just-send-8. There's still a noticeable installed base of ancient versions of sendmail, and a few deliberately misconfigured sendmail V8 installations, but unlabelled 8-bit messages have a good chance of getting through. * 8-bit MIME messages don't have such a good chance, since sendmail 8.7, by default, does Q-P conversion for MIME messages. Note that this discourages use of MIME. * Most modern MTAs proclaim 8BITMIME, even though most of them violate the 7-bit/Q-P rules in RFC 1652. I did this in qmail, for example, to protect users against sendmail 8.7's Q-P conversion. It's safe to predict that the remaining 7-bit MTAs will disappear long before the non-MIME MUAs and silent 8-bit MTAs, so just-send-8 will remain the best strategy for SMTP clients. ---Dan Set up a new mailing list in a single command. http://pobox.com/~djb/ezmlm.html