GSEC Defensible Network Architecture Practice Question
During an internal network security audit, an engineer discovers that workstations on the human resources VLAN can directly communicate with sensitive database servers on the finance VLAN without passing through a filtering device. Which foundational architectural control is missing from this environment?
⚠ Common exam trap
Examinees often select standard routing protocols or VLAN creation as solutions, confusing network connectivity with security segmentation and failing to realize that default VLAN routing permits unrestricted traffic.
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
✓
Enforcing inter-VLAN access control lists or deploying an internal firewall to inspect and restrict traffic between functional zones.
Micro-segmentation and internal routing firewalls are essential for enforcing least privilege communication between distinct functional business units. When VLANs reside on a core router or multi-layer switch without inter-VLAN access control lists, traffic flows freely between security zones. Implementing internal firewalls between these segments ensures that human resources workstations only access authorized HR applications.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Deploying a high-availability server load balancer in front of the human resources workstation subnet.
Why it's wrong here
Server load balancers distribute inbound application traffic across multiple backend servers to ensure high availability and scalability. They are not designed to enforce security segmentation policies or restrict unauthorized east-west traffic between distinct corporate functional user VLANs.
- ✗
Upgrading all edge routers to support Border Gateway Protocol with strict cryptographic route validation.
Why it's wrong here
Border Gateway Protocol is an exterior gateway protocol designed to exchange routing information between autonomous systems across the public internet. Applying BGP internally does not resolve inter-VLAN security isolation issues or replace internal access control lists.
- ✓
Enforcing inter-VLAN access control lists or deploying an internal firewall to inspect and restrict traffic between functional zones.
Why this is correct
Inter-VLAN access control lists or internal firewalls enforce strict boundaries between separate network segments. Implementing this control ensures that traffic between the human resources VLAN and the finance VLAN is explicitly filtered according to the principle of least privilege.
- ✗
Replacing all traditional dynamic host configuration protocol scopes with static IP address assignments.
Why it's wrong here
Static IP addressing does not provide network isolation or security filtering between VLANs. Devices with statically assigned IP addresses on the same routed network infrastructure can still communicate freely unless explicit packet filtering controls are enforced.
Visual reference
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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 GIAC exam blueprint
This GSEC practice question is part of Courseiva's free GIAC 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 GSEC exam.