[BlueOnyx:01210] Re: e-mail alias problem

[Chris Gebhardt - VIRTBIZ Internet]

Rodrigo Ordonez Licona wrote:
> Weird, 
> 
> 
> I have used cnames in all platforms (RAQ,BQ,BO), To alias Websites hosted
> elsewhere (not on BQ or BO) without problems. And helped me get rid of ugly
> names  Like: cameras.noip.org.
> 
> My 2 cents.

To clarify:  It is my position that CNAMEs can serve a legitimate 
purpose.   However, that purpose is NEVER for a mailserver.

Ralf Q reminded us earlier of the particular RFC this comes from, so I 
have looked up the particular section and am pasting it here for 
convenience sake:
5.2.2  Canonicalization: RFC-821 Section 3.1
          The domain names that a Sender-SMTP sends in MAIL and RCPT
          commands MUST have been  "canonicalized," i.e., they must be
          fully-qualified principal names or domain literals, not
          nicknames or domain abbreviations.  A canonicalized name either
          identifies a host directly or is an MX name; it cannot be
          CNAME.


So, to sum up:  NEVER EVER use a CNAME in an MX.

-- 
Chris Gebhardt
VIRTBIZ Internet Services
Access, Web Hosting, Colocation, Dedicated
www.virtbiz.com | toll-free (866) 4 VIRTBIZ