N10-009 Question 18
Single answerA company is moving a customer-facing web application from a single physical server to multiple virtual web servers hosted in a private cloud. Users must continue to access the application through one public URL, and the company wants traffic automatically distributed across the web servers so a single server failure does not take down the site. Which appliance should the network administrator deploy to best meet these requirements?
- A
Load balancer
- B
IDS sensor
- C
Proxy server
- D
NAS device
Show answer and explanation
Correct answer: A
Explanation
The best answer is a load balancer because the requirement is to present one public-facing service while distributing traffic across multiple backend web servers for redundancy and scalability. This matches the core function of a load balancer, which can perform health checks and stop sending traffic to failed nodes. In real deployments, load balancers may be physical or virtual appliances and are commonly used in front of web farms and application clusters. By contrast, IDS appliances focus on detection, proxy servers primarily mediate traffic rather than serving as the standard answer for balancing backend server loads, and NAS devices provide shared file storage rather than application traffic management. These distinctions align with common vendor documentation and standard network design best practices for high-availability web services.
- A. Correct.
Correct. A load balancer sits in front of multiple application servers and distributes client sessions or requests across them. This allows users to connect through a single address while improving availability and scalability. If one virtual web server fails, the load balancer can stop sending traffic to it and continue using the remaining healthy servers. This is a common design for web applications in both physical and virtual environments.
- B. Incorrect.
Incorrect. An IDS monitors traffic and generates alerts when suspicious activity is detected, but it does not distribute application traffic across multiple servers. Someone might choose this option because IDS appliances are commonly deployed near critical services, but their purpose is detection, not server redundancy or session distribution.
- C. Incorrect.
Incorrect. A proxy server acts as an intermediary for client requests or server responses, depending on whether it is forward or reverse proxy. While some reverse proxies can provide load-distribution features, the best answer in Network+ terminology for automatically balancing traffic across multiple servers behind one public service is a load balancer. Choosing proxy reflects a partial understanding of traffic mediation but misses the primary appliance designed for this use case.
- D. Incorrect.
Incorrect. NAS provides file-level storage over the network, typically using protocols such as SMB or NFS. It is used for shared storage, backups, and file access, not for distributing incoming web traffic across servers. A candidate might select NAS because the scenario mentions multiple virtual servers, but storage does not solve the availability and traffic-distribution requirement described.