Path: utzoo!attcan!lsuc!eci386!clewis
From: clewis@eci386.uucp (Chris Lewis)
Newsgroups: comp.mail.misc
Subject: Re: sigh (was Re: Short-circuiting a route)
Message-ID: <1989Jul13.153336.3175@eci386.uucp>
Date: 13 Jul 89 15:33:36 GMT
References: <1062@aber-cs.UUCP> <59767@uunet.UU.NET> <3648@ncar.ucar.edu> <3842@phri.UUCP>
Reply-To: clewis@eci386.UUCP (Chris Lewis)
Organization: R. H. Lathwell Associates: Elegant Communications, Inc.
Lines: 68

In article <3842@phri.UUCP> roy@phri.UUCP (Roy Smith) writes:

>  I was thinking of not
>touching bang paths at all but doing lookups on person@host.UUCP type
>addresses.  Does this seem reasonable?

Ignoring Internet,

It appears obvious that anyone who uses person@host.UUCP is explicitly asking
for the mail system to figure out how to send things.  Thus, do the lookup.
If there isn't such a "host" in the maps, then you may want to simply
bounce it.

It also appears obvious that anyone giving an explicit bang path
(eg: a!b!c!d) may very well know what they're doing, and it shouldn't be
touched.  The only exception is where a machine in the path doesn't have
a UUCP connect to the next machine in the path.  *Then* it makes sense
to do a lookup, starting from the rightmost and working back until
either a direct UUCP connect or a map entry is found.  Eg: don't reroute
unless you *know* the path won't work.  We'll call this "polite" rerouting...

Smail for instance, has a number of options that when set properly implement
something close to this.  But, for some reason many major sites insist on
using full (which we can call "aggressive" or "rabid") rerouting.  Which,
given the (unavoidable) state of the maps seems downright silly.  If I 
had a penny for every mail message of mine that got black-holed because 
of X (where X stands for my private hall-of-infamy list of demon-mailer 
machines from hell, and are marked "dead" in my pathalias runs)...

Can you just imagine if two rabid-rerouters thought that the best way to
site "foo" was thru each other?

Why is this so difficult to understand or implement?  Why do people
explicitly break it?  (I had some trouble turning it on after applying
some patches to smail 2.5 and the author of the patches just
simply didn't seem to care that he had partially broken polite rerouting)

In article <1024@ultb.UUCP> L.M. Barstow (lmb7421@ultb.UUCP) wrote:

>We are also currently under the bane of a mail re-router, one popularly
>known as pathalias :(  I don't care if this program has existed for
>years, it doesn't work like it could...I would much rather pathalias
>left alone any routing which had specific routing directions still
>imbedded. (ie, if there were further bang-paths in the routing, send to
>the next machine in the path...don't try to re-route what is probably a
>perfectly legal routing...

It ain't pathalias that's doing it, it's the ^&@*$) SA who explicitly
turned on full (rabid) autorouting in their mailing software (smail,
sendmail or whatever).  Pathalias merely creates a list of paths to
machines from the maps, it doesn't do anything to mail, unless the
mailer explicitly chooses to consult the list.

On the other hand, MANY times I'm very happy that quite a few machines
are doing at least polite rerouting.  I run a mailing list, keeping
track of just 50 explicit paths is something I'd rather not do.
Yes, I do have to tweak some of them - Several paths have a few nodes
mentioned in them so as to get to machines not in the map, or where
I know that some links in a pathalias-generated path don't work.

It works pretty well - the only bounces I get are when either the user
or the destination machine disappear.  Does *anyone* know what happened
to "videovax"?
-- 
Chris Lewis, R.H. Lathwell & Associates: Elegant Communications Inc.
UUCP: {uunet!mnetor, utcsri!utzoo}!lsuc!eci386!clewis
Phone: (416)-595-5425