SSCP Network and Communications Security Practice Question
A security engineer is designing a network segmentation strategy to isolate a DMZ containing public-facing web servers from the internal corporate network. Which TWO controls should be implemented? (Select two)
⚠ Common exam trap
SSCP often tests the difference between preventive and detective controls, and candidates may select IDS or NAC as segmentation controls when they are not.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Separate VLANs for DMZ and internal networks
Option A is correct because placing the DMZ and internal network in separate VLANs provides Layer 2 segmentation, preventing broadcast traffic and direct frame-level communication between the two zones unless explicitly routed through a Layer 3 device. Option B is correct because a firewall enforcing least privilege between zones is the core segmentation control: it allows only required inbound traffic (e.g., TCP 443 to the web servers) into the DMZ and restricts outbound DMZ-to-internal traffic, blocking lateral movement if a public-facing server is compromised. Option D is not sufficient on its own because a separate IP subnet alone does not enforce traffic filtering; routing between subnets can still occur without a firewall policy. Option C does not belong because NAC controls endpoint admission to the network and does not segment an existing DMZ from the internal network. Option E does not belong because an IDS only monitors and alerts on traffic; it does not enforce segmentation or block unauthorized flows.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Separate VLANs for DMZ and internal networks
Why this is correct
Separate VLANs provide Layer 2 isolation, ensuring broadcast traffic and direct frame-level communication cannot pass between the DMZ web servers and internal hosts. This satisfies the segmentation requirement by enforcing distinct logical network boundaries, with inter-VLAN routing then controlled by a firewall applying least-privilege rules.
- ✓
A firewall that only permits necessary inbound traffic to the DMZ and restricts outbound traffic from the DMZ to internal
Why this is correct
Enforcing least-privilege filtering at the DMZ boundary satisfies the isolation constraint: inbound traffic is limited to required services, while outbound restrictions prevent a compromised web server from initiating connections into the internal corporate network, blocking lateral movement.
- ✗
Network Access Control (NAC) on all endpoints
Why it's wrong here
NAC governs endpoint admission to the network, not traffic between the DMZ and internal segments, so it leaves the boundary uncontrolled. It is tempting because NAC supports segmentation goals generally, and it would be correct for controlling device access to the corporate LAN, not for isolating a DMZ.
- ✗
A separate IP subnet for the DMZ
Why it's wrong here
A separate IP subnet provides logical addressing separation but no enforcement; routing between subnets still permits traffic unless a filtering device sits between them. It is tempting because subnetting is a segmentation building block, and it would be correct combined with firewall rules or ACLs, but alone it isolates nothing.
- ✗
An intrusion detection system (IDS) monitoring traffic between segments
Why it's wrong here
An IDS only monitors and alerts on traffic between segments; it cannot enforce the isolation the DMZ requires. It is tempting because visibility into east-west traffic supports defence in depth, and it would be correct alongside a firewall, but segmentation itself demands an enforcing control.
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Same concept, more angles
1 more way this is tested on SSCP
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company is designing a network with multiple security zones. Which TWO of the following are best practices for network segmentation? (Select TWO)
medium- ✓ A.Place a firewall between each security zone to enforce traffic filtering.
- B.Use a single flat network to reduce complexity.
- ✓ C.Implement VLANs to logically separate traffic within a switch.
- D.Disable logging on inter-zone firewalls to improve performance.
- E.Place all servers in the same broadcast domain for easier management.
Why A: Option A is correct because placing a firewall between each security zone enforces traffic filtering and access control at zone boundaries, which is the core principle of defense-in-depth segmentation — inter-zone traffic should be inspected and permitted only per policy rather than flowing freely. Option C is correct because VLANs (IEEE 802.1Q) logically separate traffic at Layer 2 within a switch, limiting broadcast domains and isolating hosts even when they share physical infrastructure, which is a standard segmentation technique. Option B is wrong because a single flat network removes all segmentation boundaries, allowing unrestricted lateral movement and broadcast propagation. Option D is wrong because disabling logging on inter-zone firewalls destroys the audit trail and visibility needed to detect and investigate policy violations. Option E is wrong because putting all servers in one broadcast domain increases attack surface and broadcast traffic, directly contradicting segmentation best practices.
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official ISC2 exam blueprint
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.