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From: del@thrush.mlb.semi.harris.com (Don Lewis)
Newsgroups: comp.mail.uucp
Subject: Re: rerouting to an absolute address
Message-ID: <1990Aug7.235922.18140@mlb.semi.harris.com>
Date: 7 Aug 90 23:59:22 GMT
References: <1990Aug6.230109.4220@ibmpa> <1990Aug7.081953.6108@terminator.cc.umich.edu> <1990Aug7.134658.23389@Octopus.COM>
Sender: news@mlb.semi.harris.com
Organization: Harris Semiconductor, Melbourne FL
Lines: 38

In article <1990Aug7.134658.23389@Octopus.COM> pete@octopus.COM (Pete Holzmann) writes:
>I always thought that turning foo.com into an officially registered domain
>meant that it is up to foo.com to define what anything.else.foo.com means,
>including whether or not it is a valid address.
>
>If foo.com is not directly connected to the Internet, then it cannot answer
>any queries regarding anything.else.foo.com. peter, are you saying that
>this is a vvvvv wrong use of domains?
>
>If so, what in the world am I supposed to do? Go bug my nameserver every
>time I add a subdomain? That sounds like a pain in the neck, for me and
>for them! They didn't sign up for a hassle like that.
>
>Seems to me that a mailer should look at something.else.foo.com, and take
>the longest 'published' FQDN out of it. In this case, just foo.com, and
>send the message there. It is up to foo.com to decide what to do with
>the rest!

This is what wildcard MX records are for.  If you have:

foo.com			IN	MX	10	mail.gateway
*.else.foo.com		IN	MX	10	mail.gateway
bar.else.foo.com	IN	MX	10	another.gateway

in the zone file for foo.com, mail addressed to user@bar.else.foo.com
will be sent to another.gateway, which will forward it to bar.else.foo.com.
Mail addressed to user@foo.com, user@something.else.foo.com,
user@anything.else.foo.com, etc. will be forwarded via mail.gateway.
Mail to user@some.junk.foo.com will be bounced without being forwarded
to any of the foo.com machines (or its gateways), because DNS doesn't
know if the existance of any such hosts.

The name server software has the flexibility to tell the mailer to
do what you want. You just have to set up the zone file properly first.
--
Don "Truck" Lewis                      Harris Semiconductor
Internet:  del@mlb.semi.harris.com     PO Box 883   MS 62A-028
Phone:     (407) 729-5205              Melbourne, FL  32901