220-1101 Question 65
Single answer110 – Post Office Protocol 3 (POP3)A technician is configuring a user's email client after migrating the user to a new desktop. The user says they want to download messages from the ISP's mail server to the local PC and read them even when the internet connection is unavailable. The ISP's documentation specifies that incoming mail should use POP3. Which incoming mail server port should the technician configure for standard, non-encrypted POP3 access?
- A
25
- B
110
- C
143
- D
993
Show answer and explanation
Correct answer: B
Explanation
This question tests practical email client configuration knowledge. POP3, or Post Office Protocol version 3, is commonly used to retrieve email by downloading messages from a mail server to a local client, which supports offline reading. For standard non-encrypted POP3, the correct port is 110. By comparison, SMTP commonly uses port 25 for sending mail, IMAP uses port 143 for standard access, and secure IMAP uses port 993. In real-world support scenarios, technicians must match the correct protocol and port based on provider documentation and whether encryption is required. Common references include ISP email setup guides and standard port assignments maintained by IANA.
- A. Incorrect.
Incorrect. Port 25 is traditionally used for SMTP message transfer, especially for sending mail between servers or from a client to a mail server. A technician might choose this because SMTP is associated with email, but it is not the standard port for retrieving email with POP3.
- B. Correct.
Correct. Port 110 is the standard port for POP3 without encryption. POP3 is used by a client to retrieve email from a mail server, typically downloading messages to the local device for offline access.
- C. Incorrect.
Incorrect. Port 143 is the standard port for IMAP, not POP3. Someone might choose this because IMAP is also an incoming mail protocol, but IMAP is designed to synchronize mail with the server rather than primarily download it for local storage.
- D. Incorrect.
Incorrect. Port 993 is used for IMAP over SSL/TLS (IMAPS). This is a plausible distractor because it is a secure incoming mail port, but it does not apply to POP3. Secure POP3 typically uses port 995, not 993.