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From: taylor@hplabsc.UUCP
Newsgroups: news.software.b
Subject: Re: Sending Email to People who post to the USENET
Message-ID: <1365@hplabsc.UUCP>
Date: Sat, 28-Feb-87 20:40:28 EST
Article-I.D.: hplabsc.1365
Posted: Sat Feb 28 20:40:28 1987
Date-Received: Sun, 1-Mar-87 17:15:34 EST
References: <2131@ncoast.UUCP> <1354@hplabsc.UUCP> <4251@videovax.Tek.COM>
Reply-To: taylor@hplabsc.UUCP (Dave Taylor)
Organization: Hewlett-Packard Labs, Palo Alto, CA
Lines: 57

Donald M. Craig talks about a couple of things that I wasn't talking about
in my posting:

>But if I am being wicked and specifying a delivery path that avoids, say
>ihnp4, I don't want hplabs putting it back.   

That's fine.  I am not talking at all about dynamic re-routing.  I'm 
talking about the situation that arises currently where people simply
cannot reply to USENET postings because they have no idea how to get
to the specified host.

>The example he chose was `ncoast.UUCP'.  So I did a `pathto ncoast', and
>out of the pathalias database popped `...!cbosgd!cwruecmp!ncoast'.
>Which is two hosts shorter than the result obtained from shortening
>the news reply path.  

Okay.  That's fine.  Now go and tell me how many lines are in your
pathalias database.  I obtained the rewrite (which I freely admit
isn't ideal by any means) by using a 'pathalias' file of *23* lines.
In fact, I extracted ~350 arbitrary paths from our usenet archive
and ran them through the program  -  62% of them were shortened, 
an average of 3.94 hops.  One route had *20* hops removed by noting
that the machine two from the source was 'seismo'.  Again, this is
with a list of only 23 host routes...

(which, of course, is tons easier to maintain too)

> It seems Mr. Taylor's efforts would be better
> placed by implementing automatic updating of his pathalias database.

But this ignores the fundamental problems of the pathalias database
solution to mail routing - 1. it is inherently a static system since
people just do *not* update their individual host information on an
hourly basis, 2. it is inherently static since there is a latency time
between administrators saying "we have this connection" and the news
being posted to 'the world', propagating around, and being fed to a
program on my host, and 3. we are seeing a blossoming of hosts and are
rapidly approaching the point where the pathalias stuff doesn't even
make sense as a solution (hence one of the motivations behind moving
to domains anyway) and are fooling ourselves if we think we can maintain
10,000+ *up-to-date* addresses...

The scheme I'm proposing is a bandaid, for one thing, but is designed
to use the inherently dynamic article Path: information.  As I have said
above, it certainly tends to improve the paths over simply using the
Path: line for those hosts that aren't willing to spend the time and/or
money to maintain the massive pathalias database.  Furthermore, I think
that we could arrive at a fine middle-of-the-road solution whereby there
would be, say, a local pathalias file of no more than 100 hosts which
would allow users to reply to USENET postings with an excellent chance
that not only is the return address valid, but is also near to ideal.

It's at least something to think about...

I'll continue my experiments...	*maniacal laugh*

						-- Dave Taylor