Quick Answer
The answer is 802.1X, the IEEE standard for port-based network access control (NAC). This protocol is correct because it authenticates devices at the data link layer before granting access to either wired or wireless networks, typically using an authentication server like RADIUS to validate credentials. On the Systems Security Certified Practitioner (SSCP) exam, this question tests your understanding of how NAC enforces access policies across heterogeneous environments, often appearing in scenario-based items where a company must secure both physical switch ports and Wi-Fi connections. A common trap is confusing 802.1X with VPN protocols or simple MAC filtering, which lack the robust, server-based authentication that 802.1X provides. Remember the memory tip: “One X marks the port” — 802.1X controls access at each port entry point, making it the single standard for wired and wireless NAC.
This SSCP practice question tests your understanding of network and communications security. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company wants to enforce network access control (NAC) for both wired and wireless devices. Which protocol is used for this purpose?
802.1X
802.1X provides port-based authentication for NAC.
SNMP (Simple Network Management Protocol)
Why wrong: SNMP manages devices, not access control.
EAP (Extensible Authentication Protocol)
Why wrong: EAP is used inside 802.1X, but 802.1X is the standard.
PAP (Password Authentication Protocol)
Why wrong: PAP is insecure and used in PPP.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
802.1X
802.1X is the IEEE standard for port-based network access control (NAC) that authenticates devices before granting access to both wired and wireless networks. It operates at the data link layer and uses an authentication server (e.g., RADIUS) to validate credentials, ensuring only authorized devices connect to the network.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
802.1X
Why this is correct
802.1X provides port-based authentication for NAC.
Related concept
Read the scenario before looking for a memorised answer.
SNMP (Simple Network Management Protocol)
Why it's wrong here
SNMP manages devices, not access control.
EAP (Extensible Authentication Protocol)
Why it's wrong here
EAP is used inside 802.1X, but 802.1X is the standard.
PAP (Password Authentication Protocol)
Why it's wrong here
PAP is insecure and used in PPP.
Common exam traps
The trap here is confusing EAP (a framework) with 802.1X (the protocol that enforces NAC), leading candidates to pick EAP because it is directly involved in authentication, but it does not control network access itself.
Detailed technical explanation
802.1X uses a three-party architecture: the supplicant (client), the authenticator (switch or access point), and the authentication server (typically RADIUS). The authenticator controls the port state (blocked or authorized) based on EAP messages exchanged via EAPoL (EAP over LAN) for wired networks or EAP over wireless (e.g., EAP-TLS). A real-world scenario is a corporate network where a switch places an unauthenticated device in a restricted VLAN until 802.1X succeeds, then moves it to the production VLAN.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A security analyst at a medium-sized enterprise encounters this scenario during an investigation or architecture review. The correct answer reflects best practice for the specific threat or control described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Security exam questions test whether you can match controls to threats in context — not just recall definitions.
What to study next
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FAQ
Network and Communications Security — This question tests Network and Communications Security — Read the scenario before looking for a memorised answer..
The correct answer is: 802.1X — 802.1X is the IEEE standard for port-based network access control (NAC) that authenticates devices before granting access to both wired and wireless networks. It operates at the data link layer and uses an authentication server (e.g., RADIUS) to validate credentials, ensuring only authorized devices connect to the network.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 25, 2026
This SSCP practice question is part of Courseiva's free ISC2 certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SSCP exam.
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