Path: utzoo!attcan!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!uunet!mcsun!ukc!dcl-cs!aber-cs!athene!pcg From: pcg@cs.aber.ac.uk (Piercarlo Grandi) Newsgroups: comp.mail.uucp Subject: Re: Who pays the bill? Message-ID: Date: 5 Aug 90 14:18:00 GMT References: <26A738A8.725B@tct.uucp> <26B059CA.57CF@tct.uucp> <3270.26b4665b@mccall.com> <3275.26b54aab@mccall.com> emv@math.lsa.umich.edu (Edward Vielmetti) writes: emv> If you use a domain name that doesn't belong to you, you deserve to emv> lose. That simple enough? cf *.austin.ibm.com. "bob" == Bob Sutterfield writes: bob> Right. And one case of a domain name that doesn't belong to you is bob> one that doesn't exist. Ohhh ENOUGH! How many times should I remind everybody that not every name that has dots in it is an absolute domain name in the Internet? It could be a name in the Janet, or BITNET, or DECnet Internets, or in some other Internet that uses RFC/BSD syntax but is not on the Internet. It could even be a totally different different sort of name that just happens to have one at-sign and some dots in it. Lear Eliot has written that he always checks for neighbour information, so that "sgi.com!apple!user" is not rewritten to "user@apple.com", but to "apple!user@sgi.com". Now, Eliot is a very competent (if misguided! not all neighbours are in the maps) mail administrator. Most others are not. So please, please, please please, never encourage rewriting addressed beyond the first hop. Even the "I pay the bill" argument holds; you only pay the bill up to the next hop, so reroute only to it. What about people that reply to "Paths:"? Well, bounce their mail. Acknowledged bouncing is far less dangerous than random rerouting. Having absolute names on the Internet is a wonderful thing, but among Internets whose internal structure is unknown to each other you *must* use _relative_ naming, which is not source routing, but somehow implies it. Asking UUCP sites to register in the Internet is asking that the problem be not solved, but it be made disappear, by putting everybody in the Internet scheme of things. This will *never* *ever* happen. There is not just the UUCP Internet, there are also the BITNET, X.400, Janet, DECnet, and many other Internets. It will be *impossible* to have complete information on all Internets from any Internet. It would be nice if everybody had DARPA/NSF Internet absolute names, but since this is not going to happen, we should study ways to address other Internet's people reliably, formalizing some syntax for specifying _relative_ (to a naming or routing gateway) names, without using the unreliable way of using the local part of an RFC 822 address for it, which causes all sorts of problems with quoting characters that are meaningful for both Internets (hence the % hack). Some horrid examples can be concocted of dual use X.400/RFC822 addresses, for example. Just use dots and on at-sign in any component of an X.400 address, e.g. C=banana.republic,ADMD=national.post.office, and an at-sign somewhere else, e.g. ORG=SomeOrg@CapitalCity for an address like /ORG=SomeOrg@CapitalCity /ADMD=national.post.office/C=banana.republic which parser for non strict RFC822 would decompose as /ORG=SomeOrg @ CapitalCity/ADMD=national . post . office/C=banana . republic I am fairly sure that human nature being what it is, we will soon start seeing such addresses around fairly soon (just notice that @ in ASCII comes earlier in sorting order than letters...) Please, Please, PLEASE, PLEEEEAAASEEEE, do not do early name resolution, even on addresses that look like RFC822 addresses (they may not be), and do not do early route resolution, even when you are damned sure that the tail of the route contains RFC822 addresses for Internet hosts (the Internet may not be the cheapest/quickest route). Remember: you only know about directly connected, in a naming or routing sense, neighbours (which may be the entire DARPA Internet), and you only pay for transmission to them. You can do what you want to mail originating from your site (your users will be mad at you, and you are accountable to them), but only name-resolve/transport-route the first component in the name/route of in transit mail. -- Piercarlo "Peter" Grandi | ARPA: pcg%cs.aber.ac.uk@nsfnet-relay.ac.uk Dept of CS, UCW Aberystwyth | UUCP: ...!mcsun!ukc!aber-cs!pcg Penglais, Aberystwyth SY23 3BZ, UK | INET: pcg@cs.aber.ac.uk