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: UUCP path cost reduction Message-ID: Date: 5 Aug 90 13:38:06 GMT References: <11@aupair.cs.athabascau.ca> Sender: pcg@aber-cs.UUCP Organization: Coleg Prifysgol Cymru Lines: 65 In-reply-to: fitz@wang.com's message of 2 Aug 90 22:22:34 GMT "fitz" == Tom Fitzgerald writes: Something about munging the output of pathalias to do aggressive rerouting on the routes generated by it. Note that he does not want to reroute aggressively the routes he finds in mail envelopes passing thru his site; he is (hopefully) leaving fully specified mail routes alone, and does not second guess the sender. What he wants to do is to optimize the output of pathalias. My first observation is that instead of using perl, as he is thinking about, he could use and/or improve "pathprune", a free program designed to reduce the size of pathalias maps, mostly by removing redundant entries. He then continues: fitz> I really am trying to minimize the harm, that's why I'm only rewriting fitz> addresses that save 2 hops - rewrites that only save a single hop will fitz> be skipped. As long as you do this for addresses originating at your site, munging the maps is perfectly kosher. Well, almost. If you have better information on routing than other people, you should share it by submitting a map update request. fitz> That doesn't help mail from me to you though, since I can fitz> save 2 hops by delivering the mail to you via the Internet. fitz> By doing this, I can crunch addresses like these, drawn from our paths file: fitz> orac2 bu.edu!harvard!rutgers!ksuvax1!phobos.cis.ksu.edu!orac2!%s fitz> pur-phy bu.edu!harvard!ames!pur-ee!newton.physics.purdue.edu!%s fitz> caesar bu.edu!harvard!ames!indri!uakari!caesar.cs.montana.edu!%s fitz> into: fitz> orac2 bu.edu!phobos.cis.ksu.edu!orac2!%s fitz> pur-phy bu.edu!newton.physics.purdue.edu!%s fitz> caesar bu.edu!caesar.cs.montana.edu!%s fitz> and about 100 more like it. It's worth it to me. This simply means that your pathalias database is wrongly built, that means that either you are supplying the wrong link costs or there is a bug somewhere. Incidentally, the intermediate UUCP forwarders in the three examples above are nearly all on the Internet themselves (one of them is Rutgers, and they will aggressively rewrite your path, incidentally), so your three lines above are true monstrosities, which simply mean that your maps (or maps in general) are ludicrously specified. You should be specifying that the Internet is fully connected, so that if bc.edu and cd.montana.edu are both on it, there should be no intermediate step. Now the problem is "How I do this with pathalias?". Well, you could start by listing as fully connected all .edu subdomains that you know are on the Internet, in the local additions to the maps. I do not see any reason to munge the output of pathalias; you should correctly specify its input. -- 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