Path: utzoo!attcan!uunet!jarthur!usc!snorkelwacker!ira.uka.de!smurf!urlichs
From: urlichs@smurf.sub.org (Matthias Urlichs)
Newsgroups: comp.mail.uucp
Subject: Re: Paths and Precedence (Re: Question about From: lines)
Message-ID: <##/me2.1]8@smurf.sub.org>
Date: 18 Jul 90 22:19:36 GMT
References: <S2M4Q11@xds13.ferranti.com> <[$6je2.vl6@smurf.sub.org> <7619@gollum.twg.com>
Organization: University of Karlsruhe, FRG
Lines: 65

In comp.mail.uucp, article <7619@gollum.twg.com>,
  david@twg.com (David S. Herron) writes:
< In article <[$6je2.vl6@smurf.sub.org> urlichs@smurf.sub.org (Matthias Urlichs) writes:
< 
< >I'm currently running my mailer (MMDF, with the UUCP stuff somewhat modified)
< >based on the reasonable assumption that anyone hanging off me has either
< >Pathalias, is on the Internet, or is a node with one single connection (to
< >me).
< Quickly stepping in to save MMDF's ass :-)
< >Mangling Pathalias output to do the same is real easy via a simple sed script,
< >which transforms
< >	host: hop1!hop2!hop3!host!%s
< >into
< >	host: hop1!host!%s
< >and which is left as an exercise to the reader.)
< 
< My general strategy, and that of MMDF's, is that anything beyond
< the first hop in the address is left as an excercise to the next
< hop, not this hop.  The only modification of that strategy which

Caution: You are talking about addresses as they come in, probably via rmail.
I was talking about generating a routing database for those addresses.

< I would allow is to look into the address for FQDN's and route
< directly to the last one.  This might foil somebody who's trying to
< route around something but still putting FQDN's into their path.
< 
Unfortunately, that general strategy doesn't always work in an environment
where about everyone else has their own ideas on what to do to mixed-mode
addresses (defined as containing !s and either @s or %s). At least here, it
has proven to be far less hassle to modify that strategy, but only for
incoming UUCP stuff. Think of this as adjusting the incoming addresses to fit
into MMDFs view of the world. ;-)

Besides, "looking for FQDNs in a path" can also be defined as first converting
all members of the bang path into FQDNs whenever possible (you do this by
examining the maps' "system = alias1.dom.ain" lines), and _then_ looking for
the last FQDN...

< >This is based on the simple assumption that the next site along the path
< >really should know better how to get to the destination than I do, since it's
< >assumed to be closer to it.
< 
< You can't control all the sites around you.  Nor can you control what
< happens beyond your neighbors, but what happens out there will still
< go through your site occasionally.
< 
Who said anything about controlling? I am using my knowledge about my
neighbors (both what their mail admin tells me when we're setting up the link,
and what I get back when sending weird addresses (which nevertheless point
back at me) down the line) to decide which is the most intelligent address
format each can handle, and sending out that.

The other, more common way seems to be to use the lowest common base, bang
paths, and sending these to everyone. I think the former way is better.

You might also argue that sending each message separately via uux is stupid
and should be replaced by something more intelligent, like BSMTP. We're doing
that also (assuming that I get the BSMTP-sending interface to MMDF debugged
someday :-(  Receiving BSMTP already works, courtesy of a Perl script).

NB: All of the above does carry a big "IMHO", which should be obvious anyway.
-- 
Matthias Urlichs -- urlichs@smurf.sub.org -- urlichs@smurf.ira.uka.de
Humboldtstrasse 7 - 7500 Karlsruhe 1 - FRG -- +49+721+621127(Voice)/621227(PEP)