Port Number for POP3 (Post Office Protocol v3)
POP3 keyword: a mail-retrieval protocol where a client downloads emails from a mail server. The standard (non-encrypted) POP3 port number is 110, so the correct choice is (i) 110.
A related secure variant, often referred to as POP3S, typically uses port 995 for encrypted mail retrieval, but the classic POP3 default remains 110.
Footnotes
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Wikipedia (POP3). https://en.wikipedia.org/wiki/Post_Office_Protocol - Describes POP3 and common usage, including port details. ↩
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IANA Service Name and Transport Protocol Port Number Registry (pop3). https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml - Shows the official service-port mapping for POP3. ↩
POP3 & Port Numbers (quick overview)
To select the correct multiple-choice answer, focus on what “POP3” usually means in networking contexts: POP3 over plain TCP uses port 110 keyword: a transport-layer endpoint identified by a number.
keyword: the standard port a protocol uses unless configured otherwise.
Correct option: 110.
Why the other options are incorrect (in this context):
- 90, 80, 49 are commonly used by other services (e.g., HTTP-related ports for 80), not the default POP3 service port.
Footnotes
-
IANA Service Name and Transport Protocol Port Number Registry (pop3). https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml - Shows the official service-port mapping for POP3. ↩ ↩2
-
Wikipedia (POP3). https://en.wikipedia.org/wiki/Post_Office_Protocol - Describes POP3 and common usage, including port details. ↩
How to answer: What is the port number for POP3?
- 1Step 1
POP3 (Post Office Protocol v3) refers to email retrieval. Networking references typically associate POP3 with the standard port 110.
- 2Step 2
For POP3 over plain TCP, use port 110; encrypted POP3S is a different secure service commonly mapped to 995.
- 3Step 3
Choose (i) 110 as the POP3 default.
Pro Tip: POP3 vs POP3S
If a question says POP3 (not POP3S), it almost always expects 110. If it explicitly mentions TLS/SSL, it may be pointing to 995.
Don’t confuse POP3 with other mail protocols
POP3 is for retrieving mail. SMTP is typically for sending mail, and IMAP is for retrieving mail with different default ports—so ensure the question is specifically about POP3.
Where POP3 fits in the email workflow
Send mail
1Typically SMTP handles sending."
Store on server
2Messages are placed on the mailbox server."
Retrieve mail (POP3)
3Client connects to POP3 to download messages from the server on port 110."
Quick checks (FAQs)
Knowledge Check
What is the port number for POP3?