Which Protocol Provides Both Confidentiality and Authentication for a Site-to-Site VPN?

A network engineer wants to establish a site-o-site VPN tunnel using a protocol that allows for both data confidentially and authentication. Which of the following is the best choice?

IKE
AH
ESP Source Reference Answer
IPSec

Community Votes

78%

22%

78% of anonymous learners picked answer C. Votes are pick records left by other test-takers — they are not the verified answer.

Community Insight

The exam tests the distinction between ESP, a protocol within IPsec that provides both encryption and authentication, and IPsec, a suite of protocols; the trap is choosing IPsec because it is a broader term rather than a single protocol.

For a site-to-site VPN requiring both data confidentiality and authentication, ESP (Encapsulating Security Payload) is the correct protocol. Community consensus and exam comments agree that ESP, not IPsec as a whole, is the protocol-level answer on CompTIA N10-008.

The most common wrong answer is D. IPsec, because many candidates confuse the IPsec suite with the specific protocol that delivers the required security services. IPsec is a framework, while ESP is the component that actually provides both confidentiality and authentication.

Community Discussion (7 comments)

tempovpn 👍 5

It was on my exam (April 25th, 2024). I chose 'IPsec' in the exam, but it seems 'ESP' could be the answer according to the IBM's documentation - https://www.ibm.com/docs/en/zos/2.4.0?topic=ipsec-ah-esp-protocols Please someone confirms the correct answer of this question.

a87d6a4 👍 1

IPSec (Internet Protocol Security) is a suite of protocols designed to secure IP communications by providing data confidentiality, data integrity, and authentication. It can be used in conjunction with other protocols, such as AH (Authentication Header) and ESP (Encapsulating Security Payload), to ensure both authentication and encryption. ESP (Encapsulating Security Payload): ESP provides data confidentiality (encryption) and optional authentication but is typically used in conjunction with other protocols like IKE for a complete VPN solution. Thus, IPSec is the best choice as it encompasses both confidentiality and authentication, typically using ESP for these functions. That is my take on it atleast.

dadba8c 👍 2

ChatGPT Advanced Networking Tutor: "To establish a site-to-site VPN tunnel that provides both data confidentiality (encryption) and authentication, the best choice is: ESP (Encapsulating Security Payload) Explanation: IPSec is a framework of protocols that provides security services for IP networks, including encryption, authentication, and integrity. IPSec itself can use different protocols to achieve these goals. ESP (Encapsulating Security Payload), which is part of the IPSec suite, is specifically designed to provide data confidentiality through encryption as well as authentication and integrity. ESP encrypts the payload of the packet and can also include authentication of the entire packet (except for the IP header in transport mode). AH (Authentication Header), another protocol in the IPSec suite, provides authentication and integrity but does not provide encryption (data confidentiality). It only authenticates the packet and ensures it hasn't been tampered with, but it doesn't encrypt the data. Thus, ESP is the best choice for a protocol that allows both data confidentiality and authentication when establishing a site-to-site VPN tunnel."

441fa70 👍 3

ESP stands for Encapsulating Security Payload. It is a component of the IPsec (Internet Protocol Security) suite used to provide confidentiality, data integrity, and authentication of IP packets. ESP encrypts the payload and encapsulating headers of each packet, protecting the data from eavesdropping and tampering during transmission. It can operate in two modes: transport mode, which only encrypts the payload, and tunnel mode, which encrypts the entire IP packet. C

bagoguy 👍 3 Selected: C

ESP is the likely answer. The question asked for the protocol and ESP is the only one in IPsec that does authorization and encryption (confidentiality). AH is the other security protocol in IPsec and it does authorization but not encryption. IPsec is a suite of protocols. IKE is key management.

kinny4000 👍 4 Selected: C

IPSec is more accurately a suite of protocols, ESP the protocol within IPSec that authorizes and encrypts data. The question states a singular protocol must be the right answer.

Roman_Kwo 👍 2 Selected: D

IPSec most likely

Comments & Corrections

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Expert Analysis

Why the Answer Is Correct

ESP (Encapsulating Security Payload) is the correct answer because it is the protocol within the IPsec suite that provides both data confidentiality (encryption) and authentication. It encrypts the payload and optionally provides integrity and authentication, making it the best fit for a site-to-site VPN tunnel. Community comment [2] correctly notes that IPsec is a suite of protocols, and the question asks for a singular protocol, which points to ESP.

Why the Other Options Are Wrong

AH (Authentication Header) provides authentication and integrity but does not encrypt data, so it fails the confidentiality requirement. IKE (Internet Key Exchange) handles key management, not directly providing packet encryption/authentication for the data plane. IPsec is a protocol suite, not a single protocol; while it encompasses ESP, the question carefully wording "protocol" makes ESP the most precise answer. Comment [4] reinforces this by stating AH lacks encryption and IPsec is a suite.

Community Comment Notes

Several comments, including [1] and [2], highlight the confusion between IPsec and ESP. Comment [1] even admits choosing IPsec on the exam but later suspects ESP is correct based on IBM documentation. Comment [3] provides a clear definition of ESP, explaining that it protects data from eavesdropping and tampering. The majority vote (78% for C) and the explanation in comment [5] from an AI tutor both align with ESP as the intended answer.

Official Reference

https://www.ibm.com/docs/en/zos/2.4.0?topic=ipsec-ah-esp-protocols
https://www.rfc-editor.org/rfc/rfc4303 (ESP)
https://www.rfc-editor.org/rfc/rfc4301 (IPsec Architecture)

Exam Strategy

When a CompTIA question uses the specific word 'protocol', look for the exact component rather than the umbrella framework. For VPN questions, memorize the roles: ESP encrypts and authenticates, AH only authenticates, and IKE handles keys — then eliminate IPsec as a suite.

Related Analysis

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