BIND9 Forwarding Reverse DNS

Solution 1:

Please add a 'forward only;' statement to the forwarded zones:

zone "24.172.in-addr.arpa" { 
    type forward; 
    forward only;
    forwarders { 
      172.24.16.10; 
      172.24.16.11; 
    }; 
};

If that doesn't make a difference, check if the name servers 172.24.16.10; 172.24.16.11 actually respond.