Re: Wildcarded CNAMEs (slightly OT)

On Wed, 7 Jun 2006, Bill Jonas wrote:

> Is it permissible to have a wildcarded CNAME? I'm talking about,
> conceptually, a zone file that looks like this after the SOA record:
>

>   example.com.  IN NS     ns1.foo.bar.
>   example.com.  IN NS     ns2.foo.bar.
>   example.com.  IN CNAME  example.net.
> *.example.com.  IN CNAME  example.net.

>
> BIND (We're using some version of BIND 9, but I don't have access to
> our name servers) didn't answer lookup requests for example.com or
> www.example.com. The logs (viewed by the admin in charge of those
> servers) didn't show anything amiss, I don't think.

Maybe your logs show: "multiple RRs of singleton type"?

A singelton type can only have one record per name.

Also have a look at the BIND Administrator Reference Manual or at the
BIND9 FAQ. (Anyone want to buy an edited and printed copy of this book?)

Multiple CNAMEs are not allowed. Old BIND 4 worked with it. BIND 8 had an
option "multiple-cnames yes;" to allow it. And BIND 9.1.0 and newer
doesn't allow it.

The rule is from 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 rule also insures
that a cached CNAME can be used without checking with an authoritative
server for other RR types."

Jeremy C. Reed

echo ':6DB6=88>?;@69876tA=AC8BB5tA6487><' | tr '4-F' 'wu rofIn.lkigemca'
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