Xref: utzoo comp.mail.uucp:1624 comp.mail.headers:393 Path: utzoo!utgpu!attcan!uunet!munnari!munnari.oz!kre From: kre@munnari.oz (Robert Elz) Newsgroups: comp.mail.uucp,comp.mail.headers Subject: Re: what do _YOU_ mean by "all routing"?? Summary: But here we see the answer is revealed... Message-ID: <2295@munnari.oz> Date: 12 Aug 88 12:03:22 GMT References: <676@bacchus.DEC.COM> <881@vsi1.UUCP>Sender: news@munnari.oz Lines: 69 Rutgers (and a few other hosts) policy of "active rerouting" is finally exposed as the wrong thing to do in this article from Ron Natalie ... Article , ron@topaz.rutgers.edu: > The machine, being much more intelligent > (and closely coupled to the map database, which is maintained there as > well) than your average random UUCP site, Superficially this seems to say "we have the best routing info available, so we should make use of it" and it seems to be a defence of Rutgers' policy. However, what it really says is "we have different routing info from everyone else", which in any distributed routing scheme (which is what uucp routing is in the presence of active routers) is a recipe for disaster. Eg: consider routing to the fictional site "baz", and assume that its stable routing info (from some time in the past) is ...!rutgers!a!b!c!d!baz!user Now suppose rutgers learns that there's a much better route available ... ...!rutgers!foo!bar!baz!user However, unfortunately, "foo" hasn't learned this yet, Rutgers is using its private, very recent, new map info, which will be posted sometime tonight, and actually installed in foo's pathalias database at some unknown future time. "foo" still sees the best bath to "baz" as "...!rutgers!a!b!c!d!baz!user", and also being an active rerouter, rewrites the path that way. A few iterations of this and the mail ends up being bounced... Clearly, if Rutgers is given "baz!user" it should route it via "foo!bar!baz" and "foo" should just send the mail to "bar", whatever it thinks the best route is. However, if the mail appears at Rutgers addressed to "a!b!c!d!baz!user" Rutgers *must* send it to "a" if they have any desire at all to handle uucp mail rationally. Ron goes on ... > None of our clients (ether our UUCP/NEWS neighbors or members of the > Rutgers community) have complained. Ignoring Bob Webber for the minute (which is sensible at any time), I can understand this, they aren't the people who are having problems. The problems come from sites much further away, both those whose mail is being rerouted into a black whole, and those whose routing is being ignored. Earlier Ron had said ... > I would like to make is that as Associate Directory here responsible > for the expenditures on this machine, if you don't like the way it > runs, you can feel free to route your mail elsewhere. Exactly! That's why all pathalias & map users should add "-d rutgers" to their pathalias command scripts. I've been doing that (actually I think I have -a rutgers, the effect is the same in all relevant cases to me) for at least a year now. Nb: this will remain true forever .. even if Rutgers' tactic does have the effect of getting every uucp site in the world to register with the map project, and all the data is accurate, distribution of the resulting maps will never be quick enough to allow active rerouting to be used, anywhere. kre