question about CNAME and MX

[Barry Margolin]

In article <c3crrj$35n$1 at sf1.isc.org>,
 Brian Bergin <see_footer at bottom.com.no_domain> wrote:

> If I have 2 domains, comcept.net, comceptsolutions.com, why can't I do this:
> 
> Domain1: comcept.net
> 
> @                       A	66.77.187.2
> @                       MX	10	mx1.comcept.net.
> www                   CNAME	comcept.net.
> 
> 
> Domain2: comceptsolutions.com
> @                       CNAME	comcept.net
> @                       MX	10	mx1.comcept.net.
> www                   CNAME	comcept.net.
> 
> Basically, I want comceptsolutions.com to alias anything I change in
> comcept.net.  Am I missing something?

A name cannot be an alias and also have records of its own.  Since a 
delegated zone name is required to have SOA and NS records, it can't 
also have a CNAME record.

BTW, why did you even think that the second domain needs an MX record of 
its own?  It's the same as the MX record for the target of the CNAME, so 
it would automatically get it from there anyway.  Are you under the 
impression that CNAME records are only followed when looking up A 
records, and not for other records?  That's not how it works -- the name 
is an alias for *all* types of lookups.

-- 
Barry Margolin, barmar at alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***