220-801 · Question #16
Which of the following ports is used for POP3 traffic by default?
The correct answer is B. 110. POP3 (Post Office Protocol version 3) uses TCP port 110 by default for downloading email from a mail server to a local client.
Question
Which of the following ports is used for POP3 traffic by default?
Options
- A25
- B110
- C143
- D443
How the community answered
(39 responses)- B92% (36)
- C5% (2)
- D3% (1)
Why each option
POP3 (Post Office Protocol version 3) uses TCP port 110 by default for downloading email from a mail server to a local client.
Port 25 is assigned to SMTP (Simple Mail Transfer Protocol) used for sending and relaying email between servers, not for client retrieval.
Port 110 is the IANA-assigned default port for POP3 (RFC 1939), which downloads messages from the server to the client and typically deletes them from the server afterward. The secure version, POP3S, uses port 995 with TLS/SSL encryption.
Port 143 is the default port for IMAP, a different email retrieval protocol that keeps messages stored on the server.
Port 443 is reserved for HTTPS (secure web traffic) and is not associated with POP3 communication.
Concept tested: POP3 default port number
Source: https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml
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