ANS-C01 Network Implementation Practice Question
A company has deployed a web application across multiple AWS Regions using Application Load Balancers (ALBs) and EC2 instances. They want to use AWS Global Accelerator to improve performance and provide a fixed entry point. The Global Accelerator is configured with endpoints pointing to the ALBs. However, users are experiencing intermittent failures. What is the most likely cause?
⚠ Common exam trap
AWS often tests the misconception that client IP preservation is always beneficial, but the trap here is that enabling it for ALB endpoints in cross-Region setups breaks the expected traffic flow because ALBs require the source IP to be the Global Accelerator's IPs, not the client's.
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
✓
Client IP address preservation is enabled on the Global Accelerator for cross-Region endpoints.
When client IP address preservation is enabled on Global Accelerator for cross-Region endpoints, the accelerator preserves the original client IP address in the packets sent to the Application Load Balancers. However, ALBs are layer-7 load balancers that require traffic to originate from the Global Accelerator's static IP addresses, not the client's IP, for proper routing and health check responses. This mismatch causes the ALBs to reject or mishandle traffic, leading to intermittent failures.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Client IP address preservation is enabled on the Global Accelerator for cross-Region endpoints.
Why this is correct
When using cross-region endpoints, client IP address preservation must be disabled, otherwise traffic fails.
- ✗
Global Accelerator does not support multiple endpoints in different Regions.
Why it's wrong here
Global Accelerator supports endpoints in multiple Regions.
- ✗
The ALBs are not configured with health checks.
Why it's wrong here
Health checks are configured separately and would not cause intermittent failures.
- ✗
The Global Accelerator is not configured for IPv6 traffic.
Why it's wrong here
Global Accelerator supports both IPv4 and IPv6.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This ANS-C01 practice question is part of Courseiva's free Amazon Web Services 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 ANS-C01 exam.