Allow dns queries for specific subdomain x.domain.com and block rest of the queries for *.domain.com

[Manuel Ramírez]

Thank you very much for both answers.

Regards


El 11 abr. 2017 19:17, "Chris Buxton" <clists at buxtonfamily.us> escribió:

On Apr 11, 2017, at 2:19 AM, Manuel Ramírez <manuel.ramirez at grupoica.com>
wrote:

Hi,

I would like to allow queries for specific blogspot.com subdomains and
block the rest of the queries.
I have a file with several zones configured, one of those zones is  the
specific subdomain type "forward":

*zone "w.blogspot.com <http://w.blogspot.com/>" IN { type forward;
forwarders { 213.0.184.85; 213.0.184.88; };};*

and below i have the zone blogspot.com as master resolving an internal ip:

*zone "blogspot.com <http://blogspot.com/>" IN { type master; file
"/var/named/data/db.sinkhole"; };*


But is not working, always resolves the internal ip address, i thought it
evaluates the zones in order and first should forward the query for
w.blogspot.com but is always matching the other zone.
Any idea about how can i achieve my goal?


No, order is not considered. Rather, there are two separate searches:

- Is there an authoritative answer available from local data? In this case,
yes, because you have a sinkhole zone named "blogspot.com", from which an
authoritative negative answer can be derived.
- If the first search does not return an answer, then use the recursion
algorithm, including checking the cache and checking for the most specific
forwarding configuration (if any) that would apply.

Doing what you want is better solved using RPZ, as Tony Finch mentioned. To
do this, do not define these two zone statements. Instead, define a
response policy zone that says that *.blogspot.com should be blocked, but
that specific names (e.g. w.blogspot.com) should be whitelisted. Read the
BIND v9 ARM for details on how to accomplish this.

Regards,
Chris Buxton
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