Port 25 forgery involves:

Question

Options

• AManual communications with an SMTP server via telnet utility to forge header information.
• BRemoved SMTP packet headers for modification.
• CA "man in the middle" attack that provides for forgery of layer 4 of the stack
• DOpening at server, other than SMTP, on port 25 in order to capture inbound communications.

• A
  76% (37)
• B
  14% (7)
• C
  4% (2)
• D
  6% (3)

Explanation

Port 25 forgery exploits the fact that SMTP (which listens on port 25) is a plain-text, command-driven protocol - meaning an attacker can use telnet to manually connect to an SMTP server and type raw SMTP commands (HELO, MAIL FROM:, DATA, etc.), freely fabricating the sender address and headers before the server relays the message. Option A is correct because this manual telnet-to-port-25 technique is precisely what "port 25 forgery" describes.

Why the distractors are wrong:

• B - Headers aren't "removed for modification"; the attack works by composing fraudulent headers from scratch, not editing captured packets.
• C - This is not a man-in-the-middle attack, and SMTP operates at Layer 7 (Application), not Layer 4 (Transport) - two errors in one option.
• D - Opening a different server on port 25 describes a rogue/honeypot server concept, not forgery; the attack uses legitimate SMTP servers, not impostor listeners.

Memory tip: Think "telnet tricks SMTP" - port 25 forgery = telnet + manual SMTP commands = fake email identity. If you can type the commands yourself, you can lie about who you are.

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