Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A company is building a real-time chat application that relies on long-lived WebSocket connections between clients and backend servers. The application runs on Amazon EC2 instances across multiple Availability Zones. The company needs a load balancer that can distribute incoming WebSocket traffic while preserving the connection and supporting sticky sessions. Which AWS load balancing solution should the company use?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Best answer
Application Load Balancer
Correct. ALB supports WebSocket protocol natively and provides sticky sessions (session affinity) using cookies or source IP. It operates at Layer 7, making it ideal for real-time chat applications that require persistent connections and application-aware routing.
B
Distractor review
Network Load Balancer
Incorrect. While NLB can forward WebSocket traffic at Layer 4 (TCP), it does not offer native WebSocket support or application-layer features like cookie-based sticky sessions. NLB is designed for ultra-low latency and extreme performance, not for application-level session management.
C
Distractor review
Classic Load Balancer
Incorrect. Classic Load Balancer is a legacy service that works at Layer 4 and Layer 7, but it does not support the WebSocket protocol. Additionally, it lacks the advanced features of ALB and is not recommended for new applications.
D
Distractor review
Amazon Route 53
Incorrect. Amazon Route 53 is a Domain Name System (DNS) service. It can direct traffic to endpoints using routing policies (e.g., latency-based) but does not function as a load balancer. It cannot maintain sticky sessions or handle WebSocket connections directly.
Common exam trap
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Technical deep dive
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
- Static NAT maps one inside address to one outside address.
- PAT allows many inside hosts to share one public address using ports.
- Inside local and inside global describe the private and translated addresses.
- NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
- Identify inside and outside interfaces first.
- Check whether the scenario needs static NAT, dynamic NAT or PAT.
- Do not confuse NAT matching ACLs with normal packet-filtering intent.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A developer needs to launch a test server for a new application prototype. The developer logs into the AWS Management Console, selects an Amazon EC2 instance type, configures the security group, and starts the instance. The instance is running within two minutes, and the developer did not need to submit a formal request to the company's IT procurement team or wait for approval from a cloud administrator. Which essential characteristic of cloud computing does this scenario best demonstrate?
Question 2
A solutions architect is planning a new web application on AWS. The workload will include 3 Amazon EC2 instances (t3.medium) running 24/7, an Application Load Balancer, and an Amazon RDS for MySQL db.t3.small database. The architect needs to estimate the monthly cost for the first year, considering different purchasing options (On-Demand, 1-year All Upfront Reserved Instance, and Compute Savings Plan). Which AWS tool should the architect use to create this estimate?
Question 3
A company's development team frequently needs temporary test environments. A developer can log into the AWS Management Console, select an Amazon EC2 instance type, configure storage, and launch the instance within minutes without any interaction with the IT infrastructure team. This capability is an example of which essential characteristic of cloud computing?
Question 4
A company's finance team needs to analyze AWS spending in detail. They require a report that includes hourly cost data for each AWS service, each individual resource (e.g., a specific EC2 instance), and any cost allocation tags applied. The team plans to export this data to an Amazon S3 bucket and then import it into a custom business intelligence (BI) analytics dashboard. Which AWS tool should the finance team use to generate this level of detailed cost data?
Question 5
A company uses AWS for its development environment. The finance team wants to set a monthly budget of $10,000. They want to receive an email notification when the actual costs reach 80% of the budget ($8,000) and again when costs exceed the budget. The team needs a managed AWS service that can automatically send these alerts without requiring custom code or third-party tools. Which AWS service should the team use?
Question 6
A company uses AWS Organizations to manage multiple accounts. The security team needs to enforce a policy that restricts SSH access (port 22) from the internet (0.0.0.0/0) in all VPCs across all accounts. The team wants to centrally define the allowed rules and automatically apply them to newly created VPCs and security groups, while also automatically remediating any existing non-compliant security groups. Which AWS service should the team use?
FAQ
Questions learners often ask
What does this CLF-C02 question test?
Static NAT maps one inside address to one outside address.
What is the correct answer to this question?
The correct answer is: Application Load Balancer — Application Load Balancer (ALB) is the correct choice because it operates at Layer 7 (application layer) and natively supports the WebSocket protocol. ALB can route traffic based on HTTP/HTTPS headers, manage sticky sessions using cookies, and handle the long-lived connections required by real-time chat applications. Network Load Balancer (NLB) operates at Layer 4 (transport layer) and can forward WebSocket traffic, but it does not provide application-layer features such as cookie-based sticky sessions or content-based routing. Classic Load Balancer is a legacy service that does not support WebSocket. Amazon Route 53 is a DNS service and cannot load-balance traffic directly at the connection level.
What should I do if I get this CLF-C02 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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