CNAME Definition

[Derek J. Balling]

RFC1034 3.6.2:

"The domain system provides such a feature using the canonical name
(CNAME) RR.  A CNAME RR identifies its owner name as an alias, and
specifies the corresponding canonical name in the RDATA section of the
RR.  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 rule also insures that a cached CNAME can be
used without checking with an authoritative server for other RR types."

In your example, its not rejecting the 'foreign' CNAMES, its rejecting the
@ CNAME, as you have the myownjunk.com record containing a CNAME RR but
also SOA and NS RR's, which is verboten.

This has (as you can see) always been a violation of the RFC's as well.

D

At 3:03 PM -0600 2/3/01, asenec at senechalle.net wrote:
>We just upgraded to 8.2.3-REL from 8.2.2-P7,
>in response to the recent, CERT advisory and
>find that CNAME's with a zone construct of the
>form below no longer resolve.  I find nothing
>in RFC-1035 which would specifically prohibit
>such a construct, but I do note that some
>foreign registeries, such as deNIC, are now
>rejecting domains with such CNAME definition.
>
>$ORIGIN com.
>myownjunk IN   SOA  ns.theaccount.com. hostmaster.theaccount.com. (
>                2001020312 86400 7200 3600000 172800 )
>                IN  NS  ns.theaccount.com
>                IN  NS  ns2.theaccount.com
>                IN  CNAME   asenec.com.
>$ORIGIN myownjunk.com.
>mail            IN      CNAME   mail.asenec.com.
>ftp             IN      CNAME   ftp.asenec.com.
>www             IN      CNAME   www.asenec.com.
>
>Simply omitting the 'IN CNAME asenec.com.' record
>enables resolution of mail/ftp/www.myownjunk.com,
>but with 8.2.3-REL it seems impossible to resolve
>myownjunk.com when it is defined as a CNAME.
>Is it no longer possible to define a second-level
>domain as a CNAME?  If so, is there some RFC which
>declares doing so as illegal?
>
>Annette

-- 
+---------------------+-----------------------------------------+
| dredd at megacity.org  | "Conan! What is best in life?"          |
|  Derek J. Balling   | "To crush your enemies, see them        |
|                     |    driven before you, and to hear the   |
|                     |    lamentation of their women!"         |
+---------------------+-----------------------------------------+