CIW Exam Questions

Which port is used by DNS when conducting zone transfers?

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