CAS-004 Security Engineering Practice Question
A security architect is designing a network for a financial services firm. The firm requires that all data in transit between its internal microservices be encrypted and mutually authenticated, but the services run in a containerized environment where static IP addresses are not available. Which of the following is the MOST appropriate solution to meet these requirements?
⚠ Common exam trap
The trap here is assuming that any encryption method (like IPsec or server-side TLS) is sufficient, but the requirement for mutual authentication and dynamic environments points specifically to mTLS in a service mesh.
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
✓
Deploy a service mesh with mutual TLS (mTLS) between sidecar proxies.
A service mesh with mutual TLS (mTLS) provides encryption and mutual authentication for service-to-service communication. It uses sidecar proxies to manage certificates and identity without relying on static IPs, which suits containerized environments. This directly meets the requirements for encrypted, mutually authenticated traffic in a dynamic infrastructure.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Deploy a service mesh with mutual TLS (mTLS) between sidecar proxies.
Why this is correct
A service mesh with mTLS provides encryption and mutual authentication for service-to-service communication. It uses sidecar proxies to manage certificates and identity without relying on static IPs, which suits containerized environments. This directly meets the requirements for encrypted, mutually authenticated traffic in a dynamic infrastructure.
- ✗
Implement IPsec tunnels between each container host.
Why it's wrong here
IPsec tunnels are typically configured between hosts or gateways using IP addresses. In a containerized environment with dynamic IPs, managing IPsec tunnels becomes complex and does not provide per-service identity. It also does not inherently offer mutual authentication at the service level, making it unsuitable for the requirement.
- ✗
Configure a VPN concentrator that all microservices connect to for encrypted communication.
Why it's wrong here
A VPN concentrator is designed for remote access or site-to-site connectivity, not for service-to-service communication within a container cluster. It would introduce a central bottleneck and does not provide the granular, identity-based mutual authentication needed for microservices. It also does not scale well with dynamic container IPs.
- ✗
Use TLS with server-side certificates only for each microservice.
Why it's wrong here
Server-side TLS only encrypts traffic and authenticates the server to the client, but it does not provide mutual authentication. The requirement explicitly states mutually authenticated, meaning both parties must present certificates. This option fails to meet that critical requirement.
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
This CAS-005 practice question is part of Courseiva's free CompTIA 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 CAS-005 exam.