bind selective delegation, is it possible?

Kal Feher kal.feher at
Wed Mar 28 06:49:52 UTC 2007

Ack I miss pasted the zone config. The line:

> bright.home.    IN  A

Is from another zone naturally ;)    IN  A

Is the correct RR. 

On 28/3/07 11:47 AM, "Kal Feher" <kal.feher at> wrote:

> 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. (
>         2007032801
>         28800
>         14400
>         604800
>         86400 )
>                   IN  NS bright
>   *               IN  CNAME
> <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
Team Leader

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