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GSEC · Question #377

Which of the following ports is the default port for IMAP4 protocol?

The correct answer is B. TCP port 143. IMAP4 uses TCP port 143 for receiving email by default, distinct from other well-known mail and web protocols.

Networking and Core Concepts

Question

Which of the following ports is the default port for IMAP4 protocol?

Options

  • ATCP port 443
  • BTCP port 143
  • CTCP port 25
  • DTCP port 80

How the community answered

(54 responses)
  • A
    15% (8)
  • B
    76% (41)
  • C
    6% (3)
  • D
    4% (2)

Why each option

IMAP4 uses TCP port 143 for receiving email by default, distinct from other well-known mail and web protocols.

ATCP port 443

TCP port 443 is reserved for HTTPS (HTTP over TLS/SSL), not IMAP4.

BTCP port 143Correct

IMAP4 (Internet Message Access Protocol version 4) is standardized to listen on TCP port 143 for unencrypted connections, as defined in RFC 3501. The encrypted variant, IMAPS, uses TCP port 993. Port 143 is the universally recognized default for IMAP4 client-server communication.

CTCP port 25

TCP port 25 is the default port for SMTP (Simple Mail Transfer Protocol), used for sending mail between servers, not retrieving it.

DTCP port 80

TCP port 80 is the default port for HTTP (unencrypted web traffic), not email retrieval.

Concept tested: IMAP4 default TCP port number

Source: https://www.rfc-editor.org/rfc/rfc3501

Topics

#IMAP4#TCP port 143#email protocols#port numbers

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