AZ-900 Describe Azure architecture and services Practice Question
What is the purpose of Azure Load Balancer?
⚠ Common exam trap
It's easy for candidates to confuse Azure Load Balancer with Azure Traffic Manager or Azure Application Gateway, but Load Balancer operates at Layer 4 (TCP/UDP) for regional traffic distribution, not at Layer 7 (HTTP/HTTPS) or for global DNS-based routing.
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
✓
To distribute incoming network traffic across multiple backend resources
Azure Load Balancer operates at Layer 4 (TCP/UDP) of the OSI model to distribute incoming traffic across healthy backend resources, such as virtual machines or instances in a backend pool. It uses a hash-based distribution algorithm (5-tuple hash for inbound traffic) to ensure high availability and scalability by spreading requests evenly. This directly supports fault tolerance by automatically routing traffic away from unhealthy instances based on health probes.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
To cache web content at edge locations globally
Why it's wrong here
Caching web content at edge locations is a feature of content delivery networks like Azure CDN, which store copies of static assets at geographically distributed PoPs to reduce latency. Azure Load Balancer does not cache any data; it inspects each packet's headers and forwards it to a backend, without storing or optimizing content delivery from edge caches. Thus, edge content caching is not a load balancer function.
- ✓
To distribute incoming network traffic across multiple backend resources
Why this is correct
Azure Load Balancer operates at Layer 4 and uses rules and health probes to distribute TCP and UDP traffic evenly across a backend pool of virtual machines or instances. By sending traffic only to healthy backend resources, it improves availability and enables scaling by adding more instances without changing the front-end IP. This precisely matches the described purpose of distributing incoming network traffic across multiple backend resources.
- ✗
To connect on-premises networks to Azure
Why it's wrong here
A load balancer is an L4 service that forwards packets to endpoints inside a virtual network; it does not establish site-to-site or point-to-site VPN connections, nor does it provision ExpressRoute circuits. Hybrid connectivity relies on dedicated services such as VPN Gateway for encrypted tunnels and ExpressRoute for private, dedicated links to Azure. Therefore, connecting on-premises networks is not a function of Azure Load Balancer.
- ✗
To manage domain names and DNS routing
Why it's wrong here
Managing domain names, DNS zones, and routing policies is the domain of Azure DNS and Traffic Manager, which translate human-readable names and steer traffic based on geographic or latency-based rules. Load Balancer has no DNS records or name resolution capability; it simply forwards packets based on an IP address and port combination. Hence, it cannot perform domain name management or DNS routing.
Go deeper
Related to this question
Learn chapter
Azure Regions and Geographies
Key term
Azure Load Balancer
Azure Load Balancer is a cloud service that evenly distributes incoming network traffic across multiple virtual machines or resources to ensure reliability and high availability.
Key term
Scalability
Scalability is the ability of a system, network, or process to handle a growing amount of work by adding resources, either by making the existing resources more powerful (vertical scaling) or by adding more resources (horizontal scaling).
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-900 practice question is part of Courseiva's free Microsoft 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 AZ-900 exam.