Static IP for Whitelisting with Multi-AZ Deployment Using NLB and ALB
A company is planning to migrate its on-premises workload to AWS. The workload consists of a stateful web application that requires a static IP address for whitelisting by third-party services. The company will use a multi-AZ deployment. Which service should be used to meet these requirements?
Quick Answer
The answer is to use a Network Load Balancer (NLB) together with an Application Load Balancer (ALB) in a multi-AZ deployment. The NLB provides a static IP per Availability Zone for whitelisting by third-party services, operating at Layer 4 to preserve the client source IP and maintain stateful web application traffic. The ALB is then placed behind the NLB to handle Layer 7 routing, such as path-based or host-based rules, while the NLB’s fixed IP addresses remain the single whitelistable endpoint. On the AWS Certified Solutions Architect Professional SAP-C02 exam, this pattern tests your understanding of combining load balancer layers to meet both static IP and advanced routing requirements—a common trap is assuming the ALB alone can provide static IPs, which it cannot. Remember the memory tip: “NLB for the IP, ALB for the trip,” meaning the NLB anchors the fixed address while the ALB directs the traffic.
⚠ Common exam trap
Test-takers frequently confuse AWS Global Accelerator's static IPs with NLB's static IPs, but Global Accelerator is optimized for global traffic and adds unnecessary complexity and cost for a single-region multi-AZ deployment where per-AZ static IPs are sufficient for whitelisting.
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
✓
Network Load Balancer (NLB)
For a stateful web application requiring static IP addresses for third-party whitelisting in a multi-AZ deployment, only a Network Load Balancer (NLB) provides static IPs per Availability Zone. Application Load Balancer (ALB) uses a DNS name with changing IPs and does not offer static IPs. Therefore, NLB alone meets the requirement; ALB is not needed for static IP whitelisting.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Amazon Route 53
Why it's wrong here
Amazon Route 53 is a DNS service and does not provide static IPs for whitelisting; it routes traffic to other endpoints.
- ✗
Amazon CloudFront
Why it's wrong here
Amazon CloudFront is a CDN that provides static IPs but is optimized for global content delivery and adds unnecessary complexity for a single-region workload.
- ✓
Network Load Balancer (NLB)
Why this is correct
Correct. Network Load Balancer (NLB) provides static IP addresses per Availability Zone, which can be whitelisted by third-party services, and supports multi-AZ deployments.
- ✗
Application Load Balancer (ALB)
Why it's wrong here
Incorrect. Application Load Balancer (ALB) does not provide static IPs; it uses a DNS name with dynamically changing IP addresses, making it unsuitable for IP-based whitelisting.
- ✗
AWS Global Accelerator
Why it's wrong here
AWS Global Accelerator provides static IPs but is intended for global traffic optimization and adds unnecessary cost and complexity for a single-region multi-AZ deployment where per-AZ static IPs are sufficient.
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Same concept, more angles
1 more way this is tested on SAP-C02
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 wants to implement a data lake on AWS with data from multiple sources. They need to store data in its raw format and allow multiple teams to query it using different tools. Which service should be used as the central storage layer?
easy- A.Amazon DynamoDB
- B.Amazon Redshift
- ✓ C.Amazon S3
- D.Amazon RDS
Why C: Amazon S3 is the correct choice because it provides a highly durable, scalable, and cost-effective object storage service that can store data in its raw, native format (e.g., CSV, JSON, Parquet, images). It supports multiple query engines like Amazon Athena, Amazon Redshift Spectrum, and AWS Glue, allowing diverse teams to query the same data using different tools without data movement.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SAP-C02 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 SAP-C02 exam.