Path: utzoo!mnetor!tmsoft!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!uunet!fernwood!portal!apple!fair From: fair@Apple.COM (Erik E. Fair) Newsgroups: comp.mail.misc Subject: Re: Which headers may Sendmail re-write? Message-ID: <47605@apple.Apple.COM> Date: 27 Dec 90 22:18:52 GMT References: <1990Dec19.154652.11573@sceard.Sceard.COM> <25215@ucsd.Edu> <27763922.496B@tct.uucp> Organization: USENET Protocol Police, Western Gateway Division Lines: 91 I think it's time I put in my take on this issue. In the referenced article, chip@tct.uucp (Chip Salzenberg) writes: >Brian Kantor describes UCSD's setup. Two items deserve comment: > >>If the mail arriving via uucp contains a From: line like host@dom.ain, >>rmail does not alter it at all before passing it to sendmail, and when it >>leaves via uucp, we choose the greatest common denominator and issue it >>as ucsd!dom.ain!host in the outgoing From: line, and as >>"From dom.ain!host date remote from ucsd" in the uucp From line. > >This policy, however, is totally unjustifiable. As RFC822 gains even >wider acceptance among the non-Internet community, more and more >UUCP-only sites will be registered with the DNS. Why, oh why, must a >site registered with the DNS and complying with RFC822 in every way >suffer the slings and arrows of outrageous header rewriting, just >because they happen to use UUCP as their mail transport? Because they're not using SMTP to do the transport. The UUCP E-mail protocols have different rules and requirements. Because we're in the middle of a protocol conversion, when the vast majority of sites still speak the old protocol (i.e. UUCP mail), and software delivered from the vendors still assumes that standard, rather than the Internet standards. Them's the facts of life. That's why I have apple.com configured to do the same thing as Brian Kantor describes. Like it or lump it. Until UUCP has vanished from the face of the earth, or until we're all using a "bsmtp" command to transfer mail over a UUCP transport instead of "rmail", we all must speak the UUCP protocols in the original when we speak UUCP. As it happens, there is latitude within the original protocols to put domain names in a form that everyone in the UUCP universe can use them (e.g. foo!dom.ain!user). Lucky us. If you and a neighbor agree to do something different across a UUCP connection, that's cool, but don't invoke it with the "rmail" command, because doing that is changing the protocol. You're not supposed to do that. It impedes interoperability. Definitely a "no no." But what I'm really wondering is why Salzenberg and the people who agree with him want all us kind, generous, charitable gateway/forwarder sites to do all the work for him? If you wanna be smart, take RFC976 to its logical conclusion, and convert the dom.ain!user stuff back to user@dom.ain at your site, for your mailers, and enjoy the fruits of that labor. You know your own site names and what a domain name is, so this is allowed, and easy to do. Small matter of software (or configuration, where sendmail is concerned). I did exactly this sort of thing when I was last a postmaster at a pure UUCP site, six years ago. So far as my local users were concerned, it looked like Internet, smelled like Internet, and worked like Internet. They were really happy, and I didn't burden my Internet gateway site's postmaster with my internal E-mail configuration problems. You're wasting your breath (or your keyboard fingers, as the case may be) trying to convince me to do it for you, and in so doing, break E-mail to every old UUCP site that I speak to. So the answer to the original question is: sendmail can and should mung any and every header that it needs to, in order to get the job done right without breaking everyone who is compliant with the appropriate protocols for the network that they're on. The fundamental problem is that there are perhaps 100 people who understand this well enough to get it right, but tens of thousands of sites where it has to be done right, with postmasters who think that because they have read chapter 5 of the "Sendmail Installation and Operation Guide", they are therefore qualified to hack sendmail config files (and after they get it wrong, some of them even have the temerity to argue with those of us who got it right years ago!). You should see what I have to do to get E-mail in and out of AppleLink. Sometimes the transformations are just not reversible, because the destination E-mail system is too brain damaged, and it's so old and entrenched that no one will change it enough to make it work right. I expect that Delphi, CompuServe, MCImail, and GEnie will/do have similar problems in this regard. UUCP E-mail has the opposite problem - it's too simple, too close to the Internet standard, and too malleable, so people believe it can be hacked into being the Internet standard. Sorry folks, 'taint so. If that's what you want, use BSMTP over UUCP instead. Happy New Year, Erik E. Fair apple!fair fair@apple.com Apple Postmaster P.S. Karl, finish the book!