Path: utzoo!utgpu!attcan!uunet!husc6!ukma!david From: david@ms.uky.edu (David Herron -- One of the vertebrae) Newsgroups: comp.mail.uucp Subject: Re: why you should say "-d rutgers -d sun" in your pathalias command line Message-ID: <10135@e.ms.uky.edu> Date: 5 Aug 88 04:40:16 GMT References: <676@bacchus.DEC.COM> <881@vsi1.UUCP> <3674@palo-alto.DEC.COM> Reply-To: david@ms.uky.edu (David Herron -- One of the vertebrae) Organization: U of Kentucky, Mathematical Sciences Lines: 140 hmmm ... the Rutgers way of doing things wrong and the Sun way of doing things wrong. Maybe there's a connection here because Rutgers has a lot of Sun equipment as I understand it ... ? Nevermind ... In article <3674@palo-alto.DEC.COM> vixie@palo-alto.DEC.COM (Paul Vixie) writes: > > R U T G E R S > >brisco@pilot.njin.net (Thomas Paul Brisco) writes: ># In fact, there is nothing wrong will letting your MTA do all ># the routing for you. I've had very few sites bouncing back to me, ># and I _usually_ route through rutgers. > >This depends on what you mean by "all your routing". > >Rutgers does it WRONG. BIG TIME EL WRONGO. Always has, always will. > >If I send to <...!rutgers!foo!bar!person>, and rutgers looks in its map >database and says "oh, site <<>> can be reached through ...!baz!bar!user", >IT HAS JUST DONE THE WRONG THING. > > is never nec'ily the same person as . <<>> >can be contextual: and aren't nec'ily the same machine. how very true. It isn't done here, I don't know if rutgers does it or not. But you are right, it is the "wrong" thing to do. On the other hand I don't think you're taking it the way brisco@pilot.njin.net meant it. The only excuse I've ever heard for this is that "replies along news paths are always sub-optimal", never mind that you're not ever supposed to use news paths for replies ... NOTE that if 'bar' above were a full.domain.name then it's legit to re-route because full.domain.name's are unambiguous whereas unadorned uucp names in a uucp route *are* ambiguous. It seems appropriate to say somewhere in here that the only sites which have the right to use user@host.uucp are the ones who appear in the maps. > S U N > >Sun thinks it owns the world. I send mail from my home machine (vixie.uucp) >with a From: line like this: > > From: vixie!paul > >or like this: > > From: paul@vixie.UUCP (this is ugly and bad) [Most sites leave it alone, in one of those two forms ... oh, and why is the pseudo-domain version ugly? It's better than the bang form as I see it, that is it will be interpretable by non Unix machines.] [The From_ line is being added to as the message passes through the net, as described in both rmail source code and rfc976.] [Sun rewrites the header to give a reference relative to some internet host rather than leaving it as a bare thing which might or might not be known at the recipients machine ... namely, > From: vixie!paul@Sun.COM ] >This is EVIL and RUDE. Sun doesn't talk to vixie.UUCP; replies to the >message are broken, Sun.COM bounces things that come to it looking like: > > To: vixie!paul@Sun.COM In this case EVIL and RUDE are much too strong. It *is* EVIL and RUDE that Sun is munging the header and then NOT accepting the form into which it munges the header. But it is not such a bad thing to munge headers, especially when the message is going to be passing from a network where the addressing style works into one where the addressing style doesn't work or is only supported part of the time. A case in point which worked for many many years. The mailer at relay.cs.net used to accept mail from csnet members and then rewrite the header of the message to use the %-hack. That is they would end up with something like: david%uky.csnet@csnet-relay.arpa or david%ms.uky.edu@relay.cs.net (after domain conversion) Why did they do this? Well, in the beginning it was because a lot of the mailers on the arpanet wouldn't have been able to handle "david@uky.csnet" directly. But they *could* handle "something@csnet-relay.arpa" because csnet-relay.arpa is in HOSTS.TXT and can easily receive mail. If they were thinking of poor UUCP people at all they surely figured that the UUCP person would know of a uucp<->arpa gateway and use that to reach csnet-relay.arpa. Later on a lot of the csnet members acquired proper domain names but weren't directly connected to the Internet. MX records were advertised for these people, but not all mailers knew how to handle MX records. Again the %-hack comes to the rescue. Nowadays I think that relay.cs.net has stopped doing the %-hack for sites which have domain names, but still do for the few who do not. What does this have to do with vixie!paul@Sun.COM? A WHOLE LOT! The '!' thingie in there is very much the same thing as the %-hack, just in a slightly different form. Some random Internet site, say psuvm.psu.edu which I happen to know is an IBM mainframe, might not (probably) have any notion of what paul@vixie.uucp might mean. I know from personal painful experience that the mailer in the IBM TCP/IP package cannot use ANY host names which aren't in HOSTS.TXT *unless* the site has plunked down the many thousands of dollars they need to have a copy of SQL on site. They *only* way which that mailer will be able to have a chance of handling paul@vixie.uucp is *if* that data-base manager is on site. That's an example. All the reasons I gave above for csnet-relay using the %-hack also apply for Sun rewriting the headers as Paul says they do. BUT BUT BUT (I'm reminded here of Dr. Strangelove at the end of the movie when he's asking the Russian Ambassador *why* they would create such a good deterrent without *telling*anyone*) the employing [!%]-hack works a *whole*lot*better* if you support it coming back. [In fact, I'm really surprised that the !-hack isn't supported at Sun, it'd be such a trivial thing to put into a sendmail configuration, and is directly supported in MMDF]. >The mistake? Sun is rewriting HEADER sender addresses; it's only supposed >to rewrite ENVELOPE sender addresses unless the message is passing into the >internal network (inside Sun). NO. gateway sites are supposed to do appropriate header munging so that sites on both sides of the gateway can understand what the other side is saying. But like any language translation excercise it is non-trivial to do in practice and is a whole lot easier when both sides speak almost the same language. -- <---- David Herron -- The E-Mail guy <---- ska: David le casse\*' {rutgers,uunet}!ukma!david, david@UKMA.BITNET <---- <---- Looking forward to a particularly blatant, talkative and period bikini ...