In Internet services, which well-known TCP port number is assigned to NNTP (Network News Transfer Protocol) used by Usenet news servers?

Introduction / Context:
Many application protocols are associated with well-known TCP or UDP port numbers. Recognizing these mappings helps with firewall rules, troubleshooting connectivity, and interpreting network scans. NNTP, which underpins Usenet news distribution and reading, has a long-established default port.

Given Data / Assumptions:

• We are concerned with standard, unsecured NNTP.
• Transport is TCP.
• Alternate secure variants (for example, NNTPS over 563) are not the subject of this question.

Concept / Approach:
NNTP uses TCP port 119 for traditional connections. For comparison, HTTP uses 80, finger uses 79, and Gopher (historical) uses 70. Secure NNTP commonly uses TCP 563. Knowing these numbers by heart is common in networking exams and is valuable when configuring network devices.

Step-by-Step Solution:

Verification / Alternative check:
Use tools like 'telnet server 119' or 'nc server 119' (if NNTP is enabled) to observe the NNTP greeting banner, confirming the port association in practice.

Why Other Options Are Wrong:

• 80: HTTP, not NNTP.
• 79: Finger protocol.
• 70: Gopher protocol.
• None of the above: Incorrect because 119 is correct.

Common Pitfalls:
Confusing NNTP with SMTP (25) or POP3 (110) due to all being message-related protocols; each has distinct port assignments.

Final Answer:
119