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From: Joe Greco <jgreco@brasil.moneng.mei.com>
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Subject: Re: Name Server Q
To: verdell@novalink.com
Date: Thu, 21 Nov 1996 22:07:22 -0600 (CST)
Cc: freebsd-isp@FreeBSD.ORG
In-Reply-To: <3294DE17.252A@novalink.com> from "Verdell hicks" at Nov 21, 96 05:56:23 pm
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> Using Named I have CNAME entries which map to an actual entry, ie
> 
> 	somename            A       192.168.12.234
> 	news	            CNAME   loki
> 
> So at this point in time somename.novalink.com is 192.168.12.234 and
> news.novalink.com is an alias that points to somename.novalink.com.
> If you nslookup either name it hits back with the correct IP address.

This is perfectly and absolutely correct behaviour.

> somename.novalink.com, but I need it to come back with both
> somename.novalink.com and news.novalink.com.  Any help would be
> appreciated.  All of of our CNAME entries are having this problem in
> that only name maps to the ip the ip maps only to the real machine name.

Why do you "need" it to come back that way?

Good DNS policy (until you understand the exceptions) is to have a single
canonical name per address.  That means one domain name maps to precisely
one address, and this is implemented with both an "A" and a "PTR" record.

A CNAME simply lists a convenient alias by which a machine might be known.
In some cases ("news"), it might be because the machine provides a service.
In some cases ("met" CNAME "metropolis") it might be because typing in the
full name is a pain in the rump.

If you really, really want to have a reverse mapping (and there is probably
no reason to do so in this case), you assign another IP address to the
machine.  I do this with my DNS servers, for example.  "dns1.sol.net" has a
permanent IP address assigned to it, which never moves, even if the service
switches from one machine to another.  You can _always_ reach dns1 at
206.55.64.68.  However, I did this simply for the wire-down-ability.  There
would be NO need for me to have a reverse entry for dns1 if it were
implemented as a CNAME.

In general: you should have as many A records as PTR records.

... JG