BIND : Enable statistics

Error : WARNING: key file (/etc/bind/rndc.key) exists, but using default configuration file (/etc/bind/rndc.conf)

Solution:

1. Add this statement statistics-file "/var/cache/bind/named.stats"; to /etc/bind/named.conf

2.Remove or rename rndc.conf in /etc/bind

3. Add the following to /etc/bind/named.conf

include "/etc/bind/rndc.key";
controls {
inet 127.0.0.1 port 953
allow { 127.0.0.1; } keys { "rndc-key"; };
};

4.Restart bind.

Source : http://www.rainingpackets.com/bind-rndc-error-debian-ubuntu/