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SSCP · Question #439

SSCP Question #439: Real Exam Question with Answer & Explanation

The correct answer is B: Authentication Header (AH). IP protocol number 51 is assigned to Authentication Header (AH), which is part of the IPsec protocol suite. AH provides data integrity, data origin authentication, and anti-replay protection for IP packets, but does not provide encryption. Key protocol numbers to know: 1 = ICMP,

Submitted by saadiq_pk· Apr 18, 2026Network and Communications Security

Question

The IP header contains a protocol field. If this field contains the value of 51, what type of data is contained within the ip datagram?

Options

  • ATransmission Control Protocol (TCP)
  • BAuthentication Header (AH)
  • CUser datagram protocol (UDP)
  • DInternet Control Message Protocol (ICMP)

Explanation

IP protocol number 51 is assigned to Authentication Header (AH), which is part of the IPsec protocol suite. AH provides data integrity, data origin authentication, and anti-replay protection for IP packets, but does not provide encryption. Key protocol numbers to know: 1 = ICMP, 6 = TCP, 17 = UDP, 50 = ESP (Encapsulating Security Payload, the IPsec encryption protocol), and 51 = AH. TCP (A) is protocol 6, UDP (C) is protocol 17, and ICMP (D) is protocol 1.

Topics

#IP Header#Protocol Numbers#IPsec#Authentication Header (AH)

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