nsdc update implementation details

[David Prangnell]

Hi,

I have a query regarding running a manual update of nsd via:

# nsdc update

My NSD server is accepting notifications from two servers.  From my  
nsd.conf:
	# master 1
         allow-notify: X.X.X.X NOKEY
         request-xfr: AXFR X.X.X.X NOKEY
         # master 2
         allow-notify: Y.Y.Y.Y NOKEY
         request-xfr: AXFR Y.Y.Y.Y NOKEY

Are both servers sequentially queried each time the update is run?   
Or is it a random one of the two servers that answers and the second  
one ignored?

Many thanks,

David