bind selective delegation, is it possible?

Kal Feher kal.feher at
Wed Mar 28 01:47:52 UTC 2007

I feel a little dirty saying this but you could CNAME a wildcard record. A
quick test shows that it appears to work. Please note that I in no way
endorse this solution. A better approach is to improve your load balancing
technology so that it doesn't constrain you so.

The following test worked fine:

  $TTL 1W
  @ IN  SOA root.localhost. (
        86400 )
                  IN  NS bright
  *               IN  CNAME
  bright.home.    IN  A
<snip.... Further RRs below this proved to still work>

"dark ~ # curl star " returns the web page at

In your case you cname it to another domain that you can happily delegate to
the load balancers.


On 28/3/07 10:09 AM, "Mark Andrews" <Mark_Andrews at> wrote:

>> Hi,
>> I am trying to solve a DNS problem.   I am trying to delegate my
>> to another nameserver for the A record  but I still want
>> the MX record to be served by the original server.  The reason for
>> this is that I have load balancers and they expect to be delegated the
>> NS authority for the domain of the website (so I have delegated
>> with no problem)  Now the problem I am having is that I
>> also want to be able to load balance  since it is
>> quite common not to use the wwws nowadays.  The nameserver
>> functionality on these loadbalancers is primitive and they only
>> support A records.  If I put in an NS record on the master dns server
>> and delegate to my load balancers, my email breaks because
>> the DNS engines on the load balancers dont serve up MX records, only A
>> records, but the delegation is relinquishing authority from the master
>> server.  If I use a CNAME, its the same thing, it delegates the entire
>> domain and the master server becomes no longer authoritative for the
>> MX record.  Is there a way I can delegate to my load
>> balancer for A records only but retain authority for the MX records?
>> Or is there some other better way to accomplish this?
>> Thank you very much.
>> Zach
> That is not possible in the DNS.  In the DNS you delegate
> the entire namespace.
> Some load balancers can let querys fall through to another
> name server.  Note you have to take care to set such systems
> up correctly.
> Mark

Kal Feher

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