Understanding Networking Services in AWS—From Zero to Hero

AWS offers a comprehensive suite of networking services to facilitate secure and efficient communication between resources. These network services, like Amazon VPC, enable users to create isolated network environments, allowing fine-grained control over IP address ranges and subnets. Security groups act as virtual firewalls, controlling inbound and outbound traffic to AWS resources. Load balancers evenly distribute incoming network traffic across multiple targets, such as Amazon EC2 instances, enhancing availability and fault tolerance.

In this Cloud Lab, you will thoroughly explore the core network services provided by AWS, focusing on VPCs, security groups, and load balancers. You’ll create a VPC with public and private subnets in multiple Availability Zones. Then, you’ll launch an application on EC2 instances in the created VPC such that its backend is not accessible from the internet. Then, you will duplicate the application in a different Availability Zone to improve the resistance of the application. After that, you’ll create an application load balancer to distribute the back-end load and manage back-end resources in case of failure. Similarly, you’ll create the load balancer for the frontend of the application to manage requests and applications in case of failure. After that, you’ll learn about Auto Scaling and how it can improve the resistance of an application.

By the end of this Cloud Lab, you’ll have gained practical experience in creating a VPC, security group, and application load balancer, as well as launching an application on EC2 instances in the created VPC such that its backend isn’t accessible from the internet. These skills are essential for anyone working with AWS and will help you ensure the smooth deployment of your applications in a VPC with high scalability and reliability of your applications. The following is the high-level architecture diagram of the infrastructure that you’ll create in this Cloud Lab:

Why AWS networking is the foundation of everything you deploy

Most AWS issues that feel “mysterious” at first, services can’t reach each other, private resources can’t access the internet, requests time out, a load balancer won’t route traffic, usually come down to networking.

That’s why learning AWS networking is such a high-leverage skill. Once you understand the core primitives, everything else (EKS, Lambda integrations, databases, private APIs, hybrid connectivity) becomes easier to design and debug.

The AWS networking mental model you want

A useful way to approach AWS networking is to focus on a few building blocks and how they connect:

• VPC (your network boundary): A Virtual Private Cloud is your isolated network environment in AWS. It’s where you define IP ranges and decide which addresses are public, private, or internal-only.

• Subnets (where workloads live): Subnets divide a VPC into smaller network segments, typically spread across Availability Zones for resilience. Public subnets typically host internet-facing components, while private subnets host internal services, such as application servers and databases.

• Routing (how traffic moves): Route tables determine where traffic is directed, locally within the VPC, to the internet, to a NAT device, to a peered VPC, or to on-premises networks.

• Gateways (how networks connect): Internet Gateways, NAT Gateways, Transit Gateways, and VPN/Direct Connect links each serve a distinct purpose. The key is knowing which connectivity problem you’re solving: inbound internet, outbound-only internet, VPC-to-VPC routing at scale, or hybrid connectivity.

• Security controls (who can talk to whom): Security groups and network ACLs restrict traffic. Security groups are stateful and usually your main tool for workload-level access control. NACLs are stateless and operate at the subnet boundary, which is useful for additional guardrails.

Common architectures AWS networking enables

Once you can combine the primitives above, you can build most cloud networking patterns teams rely on:

• Public load balancer → private application tier → private database tier.

• Private VPC workloads with outbound internet access via NAT.

• Multi-VPC architectures connected with peering or transit routing.

• Hybrid setups where on-prem systems securely connect to AWS.

• Secure service access via private endpoints (when you want to avoid public internet paths).

How to troubleshoot AWS networking issues effectively

When something isn’t reachable, the fastest path is a checklist approach:

• Are the resources in the right subnets (public vs. private)?

• Do route tables send traffic to the right destination?

• Are security groups allowing the correct inbound/outbound ports?

• Are NACL rules blocking traffic at the subnet level?

• If internet access is needed, is the IGW/NAT configured correctly?

• If it’s cross-VPC, is the connection method (peering/TGW) and routing set up end-to-end?

This style of troubleshooting becomes a superpower on AWS, because most “service” issues are really network path issues.

What to learn next after you understand the basics

After you’re comfortable with core networking primitives, the next useful topics are:

• Designing for multi-AZ resilience and failure isolation.

• Private connectivity patterns (endpoints and internal-only access).

• Network observability (flow logs, monitoring, and packet-level debugging when needed).

• Cost optimization (NAT costs, data transfer, and architecture trade-offs).

AWS networking can seem overwhelming, but the core concepts remain consistent. Once you have the mental model, you can reason about almost any architecture AWS throws at you.