Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!usc!polyslo!steve From: steve@polyslo.CalPoly.EDU (Steve DeJarnett) Newsgroups: comp.mail.misc Subject: Re: sigh (was Re: Short-circuiting a route) Message-ID: <12495@polyslo.CalPoly.EDU> Date: 13 Jul 89 18:40:48 GMT References: <1062@aber-cs.UUCP> <59767@uunet.UU.NET> <3648@ncar.ucar.edu> <3842@phri.UUCP> <330@capmkt.COM> <14467@bfmny0.UUCP> Reply-To: steve@polyslo.CalPoly.EDU (Steve DeJarnett) Organization: Lab Rat Rumpus Room -- Cal Poly SLO Lines: 68 In article <14467@bfmny0.UUCP> tneff@bfmny0.UUCP (Tom Neff) writes: >Ah'm just a simpul country lawyuh , but isn't the following true? > > * If I am site X, and site Y is a direct neighbor of mine whom I poll > daily or better (maybe better than anyone else if it's worse than daily), > but I see a piece of incoming mail of the form a!b!X!c!d!e!Y!f!g, > then it's reasonable for me to reroute it as a!b!X!Y!f!g. It would seem that way, but take the following as an example. polyslo (my site) used to talk to a site named 'athena' (at CSU Sacramento, not the more-famous MIT athena). So along comes a message with a path of: polyslo!csun!csustan!athena!joe It would seem reasonable to rewrite this to being simply: athena!joe if I decided that I knew for sure that the athena in question was the one that I talk to directly. However, what happens if 'csustan' actually talks to 'mit-athena', or some other machine named 'athena' (perhaps on their local network). Then I have taken a piece of mail destined for 'csustan!athena!joe' and rerouted it to someplace different. Not good. In your example above, you wonder if rewriting: a!b!X!c!d!e!Y!g -----> a!b!X!Y!f!g is valid. If you're going to do the kind of rewriting you talk about, why even bother with the 'a!b!X' part, when you state that you are machine 'X'?? Why not just short-circuit to 'Y!f!g'?? Again you could have problems (if your system happened to have a common name, such as 'athena') with looking ahead and seeing something that you think is you, but really is not (if you see 'athena' in the path, you could short- circuit to yourself and continue, but what if the 'athena' listed further down the path was really 'csustan!athena', and not yourself. Again, a routing faux-pas :-) My belief is that if you have: a!c!foo.bar.edu!d!e that rewriting this to: e%d@foo.bar.edu makes sense, and SHOULD work (except that we've now seen two weeks worth of religious arguments about why this should or shouldn't be done, especially w.r.t. 'fidonet.org' and their unique problems). > * If my link to site Y is sick, then I ought to respect the longer path. True. > * If no site in the bang path is a direct neighbor of mine, then I ought > to consult pathalias for the link to the site named rightward of mine, > and leave the rest of it the hell alone. Yup. If it's all UUCP !-path stuff (with no FQDN), you probably should never reroute, given the number of sites with conflicting names. ------------------------------------------------------------------------------- | Steve DeJarnett | Smart Mailers -> steve@polyslo.CalPoly.EDU | | Computer Systems Lab | Dumb Mailers -> ..!ucbvax!voder!polyslo!steve | | Cal Poly State Univ. |------------------------------------------------| | San Luis Obispo, CA 93407 | BITNET = Because Idiots Type NETwork | -------------------------------------------------------------------------------