On Tue, Jul 19, 2011 at 08:30:17PM +0600, almahmud at ranksitt.net <almahmud at ranksitt.net> wrote a message of 18 lines which said: > Is it mandatory the same version for primary and secondary DNS. It is not even mandatory for all the authoritative name servers to run BIND. They can be of different brands. That's the beauty of standard protocols.