Question 80 of 1,621
Route 53 Latency Routing with Internal ALB and PrivateLink
A company is deploying a multi-tier web application across two AWS Regions. The application uses an Application Load Balancer (ALB) in each region, and traffic must be distributed to the closest healthy ALB using Route 53 latency-based routing. The application requires that clients maintain the same source IP address when the request is forwarded from the ALB to the backend targets. The backend targets are EC2 instances in private subnets. The company also needs to ensure that traffic between the ALB and targets stays within AWS. What should the company implement to meet these requirements?
Quick Answer
The correct answer is to deploy an internal ALB in each region with targets in private subnets, using VPC endpoints (AWS PrivateLink) for the ALB and Route 53 latency-based routing to those endpoints. This configuration preserves the client source IP address because traffic flows through the VPC endpoint to the internal ALB, which then forwards requests to the backend EC2 instances without performing source NAT, while the private subnets ensure all traffic between the ALB and targets remains within the AWS network. On the ANS-C01 exam, this scenario tests your understanding of how PrivateLink integrates with latency routing to maintain source IP transparency across regions—a common trap is assuming a public ALB or a Network Load Balancer is needed, but internal ALBs with PrivateLink are the key. Remember the mnemonic: “LIP” for Latency, Internal, PrivateLink—if you need to keep the client IP and stay inside AWS, think LIP.
⚠ Common exam trap
The trap is that many candidates assume an Application Load Balancer (ALB) or Global Accelerator can preserve the client source IP. However, ALB terminates the client connection and does not preserve the source IP. Only Network Load Balancer (NLB) preserves the source IP by default. Additionally, Route 53 latency-based routing requires a DNS endpoint; NLB provides this with its DNS name.
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 Network Load Balancer (NLB) in each region with targets in private subnets. Use Route 53 latency-based routing to the NLB.
Network Load Balancer (NLB) preserves the client source IP by default, meeting the requirement for source IP preservation. Targets must be placed in private subnets as per the given requirements, and traffic between the NLB and targets remains within the VPC, satisfying the condition that traffic stays within AWS. With an internet-facing NLB, Route 53 latency-based routing can be used to distribute traffic to the closest healthy NLB across regions. Options B, C, D, and E are incorrect: B incorrectly relies on an internal ALB with PrivateLink, which does not support Route 53 latency routing and does not preserve source IP; C and E use ALB, which does not preserve source IP; D uses Global Accelerator, which does not use Route 53 and does not preserve source IP when ALB is an endpoint.
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 Network Load Balancer (NLB) in each region with targets in private subnets. Use Route 53 latency-based routing to the NLB.
Why this is correct
Correct: NLB preserves source IP, targets in public subnets stay within VPC, and Route 53 latency routing can point to NLB's DNS name.
- ✗
Deploy an internal ALB in each region. Place targets in private subnets. Use VPC endpoints for the ALB (AWS PrivateLink) and Route 53 latency-based routing to the VPC endpoint.
Why it's wrong here
Incorrect: Internal ALB with PrivateLink cannot be used with Route 53 latency routing, and PrivateLink does not preserve client IP.
- ✗
Deploy an Application Load Balancer (ALB) with internet-facing scheme in each region. Use Route 53 latency-based routing to the ALB.
Why it's wrong here
Incorrect: Internet-facing ALB does not preserve source IP; traffic between ALB and targets uses private IPs, but client IP is lost.
- ✗
Use AWS Global Accelerator with endpoints in each region. Attach the ALB as an endpoint and enable client IP preservation on the accelerator.
Why it's wrong here
Incorrect: Global Accelerator uses anycast IP, not Route 53 latency routing, and it does not preserve source IP when the endpoint is an ALB.
- ✗
Deploy an ALB with internet-facing scheme in each region. Use Route 53 latency-based routing to the ALB. Place targets in public subnets to preserve source IP.
Why it's wrong here
Incorrect: Similar to C; ALB does not preserve source IP regardless of subnet placement.
Visual reference
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Same concept, more angles
1 more way this is tested on ANS-C01
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 has deployed an application across multiple AWS Regions using Application Load Balancers (ALBs). The company wants to route traffic to the nearest healthy endpoint using latency-based routing. Which AWS service should be used to distribute traffic across the ALBs?
medium- A.Amazon CloudFront with multiple origins.
- B.AWS Network Load Balancer with cross-zone load balancing.
- ✓ C.Amazon Route 53 with latency routing policy.
- D.AWS Global Accelerator.
Why C: Amazon Route 53 with a latency routing policy is the correct choice because it directs traffic to the ALB endpoint that provides the lowest latency for the end user, based on measured round-trip times between the user and each AWS Region. This aligns with the requirement to route traffic to the nearest healthy endpoint using latency-based routing, as Route 53 evaluates health checks on the ALBs and only considers healthy endpoints when determining the lowest latency.
Last reviewed: Jun 11, 2026
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.
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