Clarification about DNS notify

[Sherin George]

Hey Guys,

I have an issue which need some help.

I have two master DNS servers, say A & B.

A is running freebsd & B is running centos. B is running BIND 9 also.
Now, I want to add one more to this cluster say C.

I have installed centos in C with BIND 9. Now, I have copied
/etc/named.conf & /var/name from B to C. Now I restarted named in C.
Everything worked.

Now, I have a question which may be quite simple, but I couldn't find
an answer even after lot of googling. So, I would be extremely
grateful for any advice you could offer.

When I restarted named in C, I could see that C is sending DNS
notifications and B is receiving it

from /var/log/messages in C:

"Sep  9 23:53:44 serverC named[11844]: zone example.com/IN: sending
notifies (serial 20050        30401)"

from /var/log/messages in B:

Sep 9  23:53:44 serverB named[30375]: client XX.XX.XX.XX#54546:
received notify for zone 'example.com'

I checked  /etc/named.conf and I couldn't see any particular reason
for C choosing to notify B.

Any explanation to this behavior or a link to any relevant guide will
be helpful.

--
Regards,
Sherin