CNAME, MX and more

Michael Kjorling michael at
Mon Feb 4 17:23:00 UTC 2002

Hash: SHA1

On Feb 4 2002 10:04 +0100, Paco Orozco wrote:

> Hiya,
> Imagine this scenario:
> Scenario 1:
>		IN	A
>		IN	MX	10
> 			IN	MX	20
> Is this possible??? Is there any mistake?

You don't define A records for mailhost[12] Other than that
there is no problem with this DNS data, syntactically speaking.

> Scenario 2:
>		IN	MX	10
> 			IN	MX	20
> Is this possible??? Is there any mistake???
> Thanks

This must be one of the most frequently asked questions around here.
Try searching for "CNAME and other data" in the archives. RFC 1034
section 3.6.2:

"If a CNAME RR is present at a node, no other data should be present;
this ensures that the data for a canonical name and its aliases cannot
be different."

This restriction has been lessened recently in that SIG, NXT and KEY
records are allowed alongside CNAMEs, for DNSSEC purposes (though I
don't remember which exact RFC codifies this off the top of my head).

Any questions?

Michael Kjörling

- -- 
Michael Kjörling  --  Programmer/Network administrator  ^..^
Internet: michael at -- FidoNet: 2:204/254.4   \/
PGP: 95f1 074d 336d f8f0 f297 6a5b 2aa3 7bfd 8a70 e33e

``And indeed people sometimes speak of man's "bestial" cruelty, but
this is very unfair and insulting to the beasts: a beast can never be
so cruel as a man, so ingeniously, so artistically cruel.''
(Ivan Karamazov, in Dostoyevsky's 'The Brothers Karamazov')

*** Thinking about sending me spam? Take a close look at
*** before doing so.
Version: GnuPG v1.0.6 (GNU/Linux)
Comment: Public key is at


More information about the bind-users mailing list