Which port is used by DNS when conducting zone transfers?

A.
UDP port 53

B.
UDP port 23

C.
TCP port 53

D.
TCP port 23

Explanation:
A zone transfer uses TCP port 53. All other DNS requests use UDP 53.
Incorrect Answers:
A: UDP port 53 is used for all other DNS calls and requests, but not the zone transfers.
B: Port 23 is not used for UDP, but port 23 is reserved for Telnet
D: TCP Port 23 is Telnet