Networking Protocols Interview Question:

Why DNS use both TCP and UDP ports. And for which purpose it uses TCP and UDP?

Submitted by: Administrator

DNS uses TCP for Zone Transfer over Port: 53
DNS uses UDP for DNS Queries over Port: 53
A client computer will always send a DNS Query using UDP
Protocol over Port 53. If a client computer does not get
response from a DNS Server, it must re-transmit the DNS
Query using the TCP after 3-5 seconds of interval.
Submitted by: Administrator