Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site peora.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!mtuxo!mtunh!mtung!mtunf!ariel!vax135!petsd!peora!jer From: jer@peora.UUCP (J. Eric Roskos) Newsgroups: net.mail Subject: Re: Mail routing -- problems showing up Message-ID: <1386@peora.UUCP> Date: Tue, 30-Jul-85 11:35:17 EDT Article-I.D.: peora.1386 Posted: Tue Jul 30 11:35:17 1985 Date-Received: Thu, 1-Aug-85 21:48:36 EDT References: <4787@mit-eddie.UUCP> <9413@ucbvax.ARPA> <543@down.FUN> Organization: Perkin-Elmer SDC, Orlando, Fl. Lines: 151 Recently, the argument over how to specify addresses has begun to flare up in this usually peaceful newsgroup again. Now, this is a necessary thing -- it is getting harder and harder to route mail, making it necessary to declare more and more "smart mailer" sites dead in our local UUCP map in order to get the mail through (since very few of these sites handle the new "All-!" syntax correctly yet). The problem is, whenever this issue comes up, everyone starts making arguments that make no sense. One person starts repeating "domain, domain" endlessly; another shouts "addresses are not routes" (substituting other synonyms whenever anybody catches on) to anyone who posts a message; and even those who appear to know what is going on begin bickering endlessly. It seems to me the following are at issue here. I've written the issues first, then gone back and written in my OPINION in brackets so you can delete it (humph, he's just a lowly uucp site way out there on the periphery, what does he know about the true enlightenment possible with Sendmail!) and just have a plain list of issues. 1) The ancient issue of the "ambiguity" between "!" and "@". Because some people run all their routing information through one parser, they can't handle the fact that during transmission via UUCP, the routing syntax is !, whereas during transmission via other means, it is often @. [But the real problem is just that we are dealing with different networks here, which until they were gatewayed together had no problems. Furthermore, except for unusual routing cases, once they were gatewayed, it was still possible very effectively to send mail following simple syntax rules, until people started using "intelligent" mailers that made these syntax rules many times more complex.] 2) Some people throw away any routing information they get, and go for the message header. This is a problem given the fact that one is allowed to default the domain, since they have to then know the domain of the originating site to interpret the address correctly. [My opinion is that you should never look at the message header until all other avenues fail. In the UUCP network, you are always given some routing information in the uux command line. Unless this is unusable, there is no reason to look at the message header at all.] 3) Some people edit the headers, when they are not the originating site. They then complain because proposals others are making don't fit well with this idea. [This is a major, serious error, and is why I have special code in our mailer to avoid seismo wherever possible, for example. You should never edit the header on messages. It makes it impossible to see who the message was sent to originally. (You can tell how to get it BACK via the "Return-Path", which you have if you aren't using a mailer that throws away all that information.)] 4) Some people feel that "esu!cs!joe" is a route, whereas "joe@CS.ESU.UUCP" is a "domain", and that the latter does not specify any routing information. They feel domains simplify how much information you have to keep at your site. When pressed to explain how this works, they say, "Simple! You just send to your local UUCP name server, who then sends to the ESU name server, who then sends it to system CS, who sends it to joe." [Of course, domains are routes; the only difference is that part of the route is ambiguous: one of several name servers at a particular level may exist. Domains are only theoretically "just addresses" because they do not HAVE to be interpreted as routes; but Peter Honeyman has pointed out that neither do uucp addresses. You can THINK of domains as simply addresses; that is one model of them. But at the implementation level, you have to interpret them as routes unless you have the entire map of all sites local to you so you can generate the entire route yourself. If you have to get someone else to do it, implicitly the domain information becomes routing information.] 5) Some people are confused about whether or not they should "optimize" routing. This means that they are confused as to whether, given a route by which some previous system has said to send the mail, they should decide on their own to send it instead by some other way: either by deciding to route it on another net instead, or by deleting some of the sites in the UUCP path. Some complain that some sites optimize; some complain that all sites don't, or that they can't find the ones that do. [My feeling is that you should never optimize routing. If a route is given that is unoptimized, either (a) the sender has problems (see 6), (b) the sender has some political reason for the routing (e.g., maybe some site has complained "do not send your mail greater than 16K through our site!"), (c) the sender knows something you don't. Our mailer here currently never optimizes a route unless the sender delivers it to our site with only an RFC822 address remaining in the routing information, or unless the next site on the route is not adjacent. I don't think you should be giving unsolicited "help" to other sites in their mail routing.] 6) Some people use USENET software which tries to send a mail message back on the path by which it came, which can be highly suboptimal. [If you have RFC822 addressing in your mailer, this problem disappears. Our mailer here, for example, has the INTERNET option turned on in the Usenet software because we generate routing information from the RFC822 address. In any case, this is a bad problem with the Usenet software, and should be solved there.] 7) Some people feel that UUCP should be just like the "real" networks in terms of naming and routing. [UUCP is a cooperative, distributed network. Having "real" addressing requires centralized mail delivery sites. When you centralize in that way, you lose one of the key qualities of UUCP. I suspect that as the user load increases, UUCP will indeed change. But that is a whole different issue, for a different line of discussion.] 8) Some people feel all gateways should rewrite addresses for the network they are gatewaying onto. [This doesn't currently work, and I believe from experience it will never work. Some gateway sites either "don't care" about UUCP, or are barely hanging on already due to staff shortages. The Mailnet gateway is an example. Furthermore, it is unreasonable to expect all gateways to understand everything there is to know about all other gateways. If you specify addresses via a or syntax, each site has to interpret only one part of the address. Otherwise, it has to interpret all parts. It is unreasonable to expect it to interpret all parts, especially when it is so easy, by simply deciding on a few simple LR or RL rules, not to do that. People are already complaining "What is this "%" syntax? What is this "^"?" That is exactly symptomatic of the problem. The part of the route should be just a string to the mailer interpreting the part. There is no reason nor justification for requiring otherwise; it makes the mailers unduly complicated, since they must always know about all other networks in the world that they are connected to. I can tell you firsthand they don't, and never will.] 9) Non-unique site names exist. [This is a definite problem. Both proposed approaches solve it, since we've just shown that the two approaches are theoretically equivalent, differing only in their CURRENT implementations: interpreting a!b!c as an address, and c@b.a as an address, you arrive at an unambiguous site name. The current argument seems based on the fact that people claim these two equivalent address syntaxes are not equivalent, and then try to argue from that. But they are equivalent. Both are both routes and addresses.] [Most of the problems would go away if people would just think about them in a coherent manner, adhering to one chosen viewpoint instead of constantly changing their stance. This is why these arguments proliferate for so long. People won't stick to what they believe. You can't make a reasonable argument from contradictory premises; yet this happens very regularly.] -- Shyy-Anzr: J. Eric Roskos UUCP: ..!{decvax,ucbvax,ihnp4}!vax135!petsd!peora!jer US Mail: MS 795; Perkin-Elmer SDC; 2486 Sand Lake Road, Orlando, FL 32809-7642 "Fvzcyvsl, fvzcyvsl." -- UQG