NNTP over SSL uses which port number?

NNTP over SSL uses which port number?

• A. 119
• B. 123
• C. 110
• D. 563

Answer: (D)

The key idea here is knowing which port numbers pair with specific protocols and their secure variants. NNTP handles newsgroup data, and the unencrypted form typically uses port 119. When you run NNTP over SSL/TLS, the secure variant uses port 563, often called NNTPS. So NNTP over SSL uses 563 because SSL/TLS is applied to the connection from the start on that port, providing encrypted communication. To place the other options in context: 119 is for plain NNTP, not encrypted; 110 is POP3 (email retrieval); 123 is NTP (network time). They don’t match NNTP over SSL, which is why 563 is the correct choice.

The key idea here is knowing which port numbers pair with specific protocols and their secure variants. NNTP handles newsgroup data, and the unencrypted form typically uses port 119. When you run NNTP over SSL/TLS, the secure variant uses port 563, often called NNTPS. So NNTP over SSL uses 563 because SSL/TLS is applied to the connection from the start on that port, providing encrypted communication.

To place the other options in context: 119 is for plain NNTP, not encrypted; 110 is POP3 (email retrieval); 123 is NTP (network time). They don’t match NNTP over SSL, which is why 563 is the correct choice.