Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 6/24/83; site ulysses.UUCP
Path: utzoo!linus!decvax!genrad!wjh12!foxvax1!brunix!ulysses!smb
From: smb@ulysses.UUCP (Steven Bellovin)
Newsgroups: net.mail
Subject: Re: Area-code as uucp domains
Message-ID: <758@ulysses.UUCP>
Date: Sat, 28-Jan-84 20:39:42 EST
Article-I.D.: ulysses.758
Posted: Sat Jan 28 20:39:42 1984
Date-Received: Thu, 2-Feb-84 01:35:14 EST
References: <426@psuvax.UUCP>
Organization: AT&T Bell Laboratories, Murray Hill
Lines: 12

I wrestled with the same routing decisions when I wrote pathalias.  I
finally ended up implementing 3 modes:  dumb (just pass the message on
to the next host), simple (route to the left-most host), and smart (route
to the right-most known host).  Rmail used simple routing; locally-generated
mail used smart routing (to handle netnews replies).  Note that if you
do any sort of routing on locally-generated routing, you're obligated to
have rmail do at least simple routing, so that replies work right.  That
is, if I'm at site A and send a note to B!foo and C!bar, and B!foo replies
to both of us, that reply will go to A!me and A!C!bar.  But if C were
routed by my mailer over several hops, the reply won't make it.  I didn't
use smart routing in rmail because I didn't want to break loop tests
or deliberately-routed mail passing through.