w2k3 server and dna - driving me crazy

good morning

can anyone please clarify on this matter

base system : w2k3 - sp2 latest updates - sbs 2k3 ( if relevant )

a simple netstat ( active ports actually ) shows dns process
linstening on nearly all UDP ports.
tcp 53 is also listening and dns is responsive.

our infrastructure includes a fedora ds server for replication, running
bind, also for replication. ( if relevant )
i just need to know (for now ) if this behaviour is expected.

thank you and have a nice day
pleite