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GCIA · Question #124

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

The correct answer is A. TCP port 143. IMAP4 (Internet Message Access Protocol version 4) listens on TCP port 143 by default for unencrypted client-server communication.

Network Traffic Analysis & Protocol Review

Question

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

Options

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

How the community answered

(22 responses)
  • A
    73% (16)
  • B
    18% (4)
  • C
    5% (1)
  • D
    5% (1)

Why each option

IMAP4 (Internet Message Access Protocol version 4) listens on TCP port 143 by default for unencrypted client-server communication.

ATCP port 143Correct

RFC 3501 defines IMAP4rev1 as operating over TCP port 143 for standard plaintext connections. This port is assigned by IANA specifically to IMAP and is the universally expected default that mail clients use when connecting to an IMAP server without SSL/TLS (IMAPS uses port 993).

BTCP port 25

TCP port 25 is the SMTP port used for server-to-server email transfer and mail submission by mail transfer agents, not for IMAP client access.

CTCP port 443

TCP port 443 is reserved for HTTPS (HTTP over TLS/SSL) and is unrelated to the IMAP email retrieval protocol.

DTCP port 80

TCP port 80 is the default port for unencrypted HTTP web traffic and has no association with the IMAP4 protocol.

Concept tested: IMAP4 default TCP port assignment

Source: https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml

Topics

#IMAP4#email protocols#port numbers#TCP ports

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