Alternative smtp servers

[Joseph S D Yao]

On Wed, May 03, 2000 at 03:50:29PM -0400, Michael Kohne wrote:
> <snip>
...
> >CNAMEs should never be used as targets of MX records.
> 
> I've been following this thread and am curious about this statement: Why
> should an MX record never point to a CNAME? 

'Cause it sez so.  ;-)

RFC 2181:

10.3. MX and NS records

   The domain name used as the value of a NS resource record, or part of
   the value of a MX resource record must not be an alias.  Not only is
   the specification clear on this point, but using an alias in either
   of these positions neither works as well as might be hoped, nor well
   fulfills the ambition that may have led to this approach.  This
   domain name must have as its value one or more address records.
   Currently those will be A records, however in the future other record
   types giving addressing information may be acceptable.  It can also
   have other RRs, but never a CNAME RR.

-- 
Joe Yao				jsdy at cospo.osis.gov - Joseph S. D. Yao
COSPO/OSIS Computer Support					EMT-B
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