Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!neat.ai.toronto.edu!lamy
From: lamy@ai.utoronto.ca (Jean-Francois Lamy)
Newsgroups: can.uucp
Subject: Re: What happens when a subdomain (actually a machine) moves?
Message-ID: <89Jun29.215547edt.10385@neat.ai.toronto.edu>
Date: 30 Jun 89 01:55:37 GMT
References: <2488@yunexus.UUCP>
Distribution: can
Lines: 32

Well, domain names are meant to name entities, and it is often desirable to
keep the distinction clear between names of machines and the name assigned to
the group of people.  

So for example when you mail to ai.utoronto.ca the intent is to identify the
AI group at U of T, not the machines (neat.ai.utoronto.ca and
ephemeral.ai.utoronto.ca that handle mail for that group -- either one will
behave properly if you drop mail on its lap destined for that domain).

Conversely, you can have more than one mail domain (intended to designate an
homogeneous group of people) living on one machine.  We actually have
theory.utoronto.ca, na.utoronto.ca and ai.utoronto.ca all served by the same
two mail machines (we generate the address depending on the person).

So the idea is that the machines die, move, but your address stays the same
as long as you stay within your organizational unit.

If what you have in mind is a division of a company being taken over and
moving from whizbang.one.com to newerbetter.two.com, then that case can be
handled by having the name server for one.com advertize that mail for
user@whizbang should now be sent to newerbetter.two.com, and for newerbetter's
mailer to accept such mail.  This is partly what the wunnerful MX records on
internet name servers are used for.  The actual message would not even go
to one.com.  This sort of improves on the postoffice situation.

In the UUCP world, whoever handles mail for two.com would redirect forcibly
mail for the whizbang gang to newerbetter for a while, I guess.

Virtually,

Jean-Francois Lamy               lamy@ai.utoronto.ca, uunet!ai.utoronto.ca!lamy
AI Group, Department of Computer Science, University of Toronto, Canada M5S 1A4