Most specific match on PTR records

[Hauke Lampe]

On 21.02.2013 19:20, Nikita Koshikov wrote:

I haven't tested this in detail but here's what I would try:

> I'm trying to "cut" /24 network from the scope of /8 network, here is
> example:
>
>          zone "11.2.10.in-addr.arpa" {
>                  type forward;
>                  forwarders { 192.168.1.23; 192.168.1.24; };
>          };
>
>          zone "10.in-addr.arpa" {
>                  type master;
>                  file "master/int/10.in-addr.arpa";
>          };
>

The local authoritative data takes precedence over a forward zone.

> 10.in-addr.arpa is just a file that returns NXDOMAIN for any 10.0.0.0/8 ip
> address. But I need to forward requests for 10.2.11.0/24 net to other dns
> servers and the above config not working.

The easiest way might be to delegate the subdomain with a static-stub:

           zone "11.2.10.in-addr.arpa" {
                   type static-stub;
                   server-addresses { 192.168.1.23; 192.168.1.24; };
           };

           zone "10.in-addr.arpa" {
                   type master;
                   file "master/int/10.in-addr.arpa";
           };

This is a "synthetic" delegation. There could be a problem if a client 
queries 2.10.in-addr.arpa. The NXDOMAIN response (instead of nodata) can 
be interpreted as "*.2.10.in-addr.arpa. doesn't exist". A "real" 
delegation in the zone file is probably better.

If your version of BIND is older than 9.8, you could try to move the 
master zone into a view and configure 10.in-addr.arpa as another forward 
zone in the client's view.


Hauke.