Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

we're trying to add an MX record to a Windows Server 2003 DNS server and getting the following error:

"A new record cannot be created. Node is a CNAME DNS record."

The domain is We create a new MX record and leave the "Host or child domain:" field blank, then we're putting "" in the "Fully qualified domain name (FQDN) of mail server:" field and leaving the default Priority of 10.

Are we missing something?

share|improve this question
up vote 6 down vote accepted

If you are trying to set an MX record for a hostname such as (for mail to and that name exists as a CNAME record instead of an A record, it would result in this error. If a host exists as a CNAME, it cannot also have other record types associated with it. You would need to re-create the hostname as an A record and then add the MX record to it.

share|improve this answer
On a BIND DNS name server, you would get "CNAME and other data (invalid)" errors showing up in logs. – netlinxman Jun 7 '09 at 1:04

RFC 2181 forbids the use of a CNAME value in a MX record:

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.

Microsoft specifically has this to say on the subject.

share|improve this answer
Correct but unrelated to the error message he got. The problem is more likely the one spotted by Justin Scott. – bortzmeyer May 20 '09 at 6:54
@bortzmeyer Eh? Justin actually said the same thing. – MikeyB May 20 '09 at 13:39

Try adding a trailing dot to ""

That's something I constantly forget, and it doesn't work without it.

share|improve this answer

Had exactly the same issue even logging onto multiple DC's directly to try and create the record.

Problem ended up being copy and pasting the information from a third party application. Seemed to be a unknown illegal Character, typing the record "manually" worked fine.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.