Which of the following ports is used by default for DNS traffic?

The correct answer is B. 53. DNS (Domain Name System) uses port 53 by default for both UDP (standard queries) and TCP (zone transfers and large responses). The other ports serve different purposes: port 25 is SMTP (email transmission), port 143 is IMAP (email retrieval), and port 3389 is RDP (Remote…

Networking

Question

Which of the following ports is used by default for DNS traffic?

Options

A25
B53
C143
D3389

How the community answered

(14 responses)

B
93% (13)
D
7% (1)

Explanation

DNS (Domain Name System) uses port 53 by default for both UDP (standard queries) and TCP (zone transfers and large responses). The other ports serve different purposes: port 25 is SMTP (email transmission), port 143 is IMAP (email retrieval), and port 3389 is RDP (Remote Desktop Protocol). Memorizing well-known ports is essential for networking and security topics on the CompTIA A+ and Network+ exams.

Topics

#DNS#port numbers#network protocols#UDP/TCP

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