Which of the following statements about Encapsulating Security Payload (ESP) is true?

Question

Options

• AIt is an IPSec protocol.
• BIt is a text-based communication protocol.
• CIt uses TCP port 22 as the default port and operates at the application layer.
• DIt uses UDP port 22

• A
  73% (43)
• B
  3% (2)
• C
  17% (10)
• D
  7% (4)

Explanation

ESP (Encapsulating Security Payload) is indeed an IPSec protocol - it's one of the two core protocols in the IPSec suite (alongside AH, Authentication Header), operating at the network layer to provide confidentiality, integrity, and authentication for IP packets.

Why the distractors are wrong:

• B is wrong because ESP is a binary/packet-based protocol, not text-based (text-based protocols include HTTP, SMTP, FTP).
• C is wrong on both counts: TCP port 22 belongs to SSH, and ESP operates at the network layer (Layer 3), not the application layer. ESP also doesn't use TCP at all - it's IP protocol number 50.
• D is wrong because UDP port 22 is not associated with ESP. ESP uses IP protocol number 50 directly; when NAT traversal is needed, it's encapsulated in UDP port 4500, not 22.

Memory tip: Think of ESP as the privacy enforcer of IPSec - it Encrypts and Secures Packets at the network layer. Remember the number 50 (IP protocol 50) - not a port, a protocol number - which distinguishes it from port-based protocols like SSH (port 22).

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