AWS Certified Advanced Networking – Specialty (ANS-C00) — Question 265

What port and protocol is used by DNS?

Answer options

• A. 80/TCP
• B. 22/TCP
• C. 80/TCP and UDP
• D. 53/TCP and UDP

Correct answer: D

Explanation

DNS primarily operates on port 53 using both UDP for standard, fast queries and TCP for larger payloads or zone transfers. In contrast, port 80 is designated for HTTP web traffic, and port 22 is reserved for SSH secure shell access.