CompTIA
N10-005 · Question #634
N10-005 Question #634: Real Exam Question with Answer & Explanation
The correct answer is B: 53. DNS (Domain Name System) uses port 53 for both UDP (standard queries) and TCP (zone transfers and large responses). To allow clients to resolve domain names via an external DNS server, port 53 must be open on the firewall. Port 20 is FTP data, port 80 is HTTP, and port 3389 is RD
Question
Which of the following ports should be allowed through a firewall to allow DNS resolution to occur to an outside DNS server?
Options
- A20
- B53
- C80
- D3389
Explanation
DNS (Domain Name System) uses port 53 for both UDP (standard queries) and TCP (zone transfers and large responses). To allow clients to resolve domain names via an external DNS server, port 53 must be open on the firewall. Port 20 is FTP data, port 80 is HTTP, and port 3389 is RDP.
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