AWS Networking and VPC

AWS Networking and VPC

Lesson 5: Networking Basics in AWS


Welcome to Lesson 5 of our "Fundamentals of AWS" series! In this module, we'll embark on a journey through the intricate world of AWS Networking. Understanding the basics of networking is crucial for architects and developers to design robust and scalable solutions. Let's unravel the mysteries of Virtual Private Cloud (VPC) and other networking components in AWS.



Our objectives for this lesson are straightforward:


1. Understand the Fundamentals of Networking in AWS:

   - Grasp the core networking components: VPC, Subnets, Route Tables.

   - Explore Elastic IP addresses and Elastic Network Interfaces (ENIs).


2. Learn About Amazon VPC and its Components:

   - Gain insights into VPC creation, configuration, and subnetting.

   - Understand how to establish VPC peering connections and connect VPCs to on-premises networks.


 1. AWS Networking Concepts:

 Overview of Networking Components:

- Virtual Private Cloud (VPC):

  - Definition: A logically isolated section of the AWS Cloud where you can launch AWS resources.

  - Example: Create a VPC with a defined IP address range like



  - Definition: Segments of a VPC's IP address range where you can place groups of resources.

  - Example: Create subnets within a VPC for different availability zones.


Route Tables:

  - Definition: Define rules, known as routes, that determine where network traffic is directed.

  - Example: Specify a route to send all internet-bound traffic to an internet gateway.


 Elastic IP Addresses and Elastic Network Interfaces (ENIs):

- Elastic IP Addresses:

  - Definition: Static IPv4 addresses designed for dynamic cloud computing.

  - Example: Associate an Elastic IP address with an EC2 instance for a persistent public IP.


Elastic Network Interfaces (ENIs):

  - Definition: Virtual network interfaces that you can attach to instances in a VPC.

  - Example: Attach an additional ENI to an EC2 instance for enhanced networking capabilities.


 2. VPC Configuration:

 Creating and Configuring a VPC:


   Step 1: Create a VPC:

     - Define the IP address range and configure DNS settings.

     - Example: Create a VPC with CIDR block



# AWS CLI command to create a VPC

aws ec2 create-vpc --cidr-block



   Step 2: Subnetting and Route Table Associations:

     - Divide the VPC into subnets for better resource management.

     - Associate route tables with subnets for controlling traffic.



# AWS CLI command to create a subnet

aws ec2 create-subnet --vpc-id vpc-xxxxxxxx --cidr-block



 3. VPC Peering and Connectivity:

 Establishing VPC Peering Connections:

- Definition: Connect two VPCs to enable instances in one VPC to communicate with instances in the other.

- Example: Establish a peering connection between VPC-A and VPC-B.



# AWS CLI command to create a VPC peering connection

aws ec2 create-vpc-peering-connection --vpc-id vpc-a --peer-vpc-id vpc-b



 Connecting VPCs to On-Premises Networks:

- Options:

  - VPN Connection: Securely connect your on-premises network to your Amazon VPC.

  - AWS Direct Connect: Establish dedicated network connections from your on-premises data center to AWS.


 4. Network Address Translation (NAT):

 Configuring NAT Gateways and Instances:

- NAT Gateway:

  - Definition: Managed network address translation service for resources in a private subnet to access the internet.

  - Example: Route outbound traffic from private subnets through a NAT gateway.



# AWS CLI command to create a NAT gateway

aws ec2 create-nat-gateway --subnet-id subnet-xxxxxxxx --allocation-id eip-xxxxxxxx



NAT Instances:

  - Definition: Manually configured EC2 instances that serve as NAT devices.

  - Example: Create an EC2 instance with a NAT AMI and configure routing.



# AWS CLI command to create a NAT instance

aws ec2 run-instances --image-id ami-xxxxxxxx --subnet-id subnet-xxxxxxxx --instance-type t2.micro



 Understanding Outbound Internet Access:

- Instances in private subnets access the internet through NAT gateways or instances.

- Use security groups and route tables to control outbound traffic.


 Example: Step-by-Step Guide to VPC Creation:


Let's solidify our understanding with a practical example:

  1. Create a VPC with a CIDR block.
  2. Establish subnets in different availability zones.
  3. Associate route tables with subnets.
  4. Create instances in each subnet and ensure communication.


This hands-on example will guide you through the process of creating a well-architected VPC.


In conclusion, networking forms the backbone of any cloud architecture, and mastering the basics is essential. By understanding AWS networking concepts and VPC configurations, you'll be better equipped to design scalable and secure solutions in the AWS cloud. Stay tuned for more AWS insights in our upcoming lessons!