Path: utzoo!utgpu!water!watmath!clyde!att!rutgers!tut.cis.ohio-state.edu!bloom-beacon!bu-cs!purdue!decwrl!vixie
From: vixie@decwrl.dec.com (Paul Vixie)
Newsgroups: comp.mail.uucp
Subject: When to reroute (Re: active rerouting)
Message-ID: <802@bacchus.dec.com>
Date: 14 Sep 88 00:10:39 GMT
References: <4740@b-tech.UUCP> <4747@b-tech.UUCP> <4748@b-tech.UUCP> <4753@b-tech.UUCP> <1426@ficc.uu.net> <6548@chinet.UUCP>
Sender: vixie@decwrl.dec.com
Organization: DEC Western Research Lab
Lines: 49

# I would rather see a standard way to explicitly request a site to re-route
# and everything else should be left alone if deliverable.

You've got the seeds of your answer: if the supposed next-hop-to-send-to is
not something you speak to "directly", feel free to reroute.  But if it's a
neighbor which you've published in the UUCP Map (which is likely, if someone
knows to try to use your connection to it), you should fulfill your implicit
promise to deliver the darned message to the neighbor.

Summary: don't reroute unless the alternative is bouncing it.

# Then news software running on machines that do not have the map data could
# pass replies off to the nearest site that knows how to route it. 

The above solution will work fine with the "mailpaths" mechanism in B News,
or with the "smart-host" mechanism in Smail.  In either case, you just
forward the message to your nearest smart router, writing up the path as
though the place you want to get to was a neighbor of the place you are
forwarding it to:

	foo!bar!smarthost!%s

...will expand "user@mumble.uucp" or "mumble!user" into

	foo!bar!smarthost!mumble!user

...and the fact that "mumble" is not a directly reachable neighbor will clue
"smarthost" in on the need to find a route.

This works.  It works today.  If we could get the rabid rerouters off their
high horse and convince them somehow to be more polite (and to honor the
implicit promise many people see in their UUCP map entry), we would all be
able to spend more time advancing the state of the art instead of wondering
why our last message to some distant friend was never answered.

I can mark active rerouters dead in my own pathalias build, but sites that
don't do that might end up either not being able to reach me (because a
rabid rerouter decided to send the mail to Italy) or, worse, All The Mail
In The Universe will suddenly start flowing through my machine because
someone mistakenly published a shortcut through my machine and some distant
large site insists that anything coming through their machine bound for
some large fraction of the internet _must_ go through my machine because
it's suddenly the "most efficient way".  Pfaa.

Don't mind me, I'm just bellyaching.
-- 
Paul Vixie
Work:    vixie@decwrl.dec.com    decwrl!vixie    +1 415 853 6600
Play:    paul@vixie.sf.ca.us     vixie!paul      +1 415 864 7013