[bitfolk] question on bind9 listening.

Hi All, Is letting bind9 listening on all interfaces a good practice? Or letting it listening on specific interface best ? If I set specific address listening, bind9 failed to start and stops listening. If i set bind9 to listen to all and block using the firewall the interface I do not it to listen to bind9 to powerdns replication did not work. Powerdns as primary here. It seems to be working if I set bind9 to listen to all interfaces and not block by the firewall. Regards, -badli