AWS Networking Fundamentals

1. Introduction

AWS Networking Fundamentals focuses on the essential networking components within the Amazon Web Services (AWS) cloud. Understanding these components is crucial for deploying secure and reliable applications.

2. Key Concepts

Cloud Networking: The practice of delivering networking infrastructure in a cloud environment.
VPC: Virtual Private Cloud allows you to create isolated networks within the AWS cloud.
Subnets: Subdivisions of a VPC that facilitate better organization and security.
Route Tables: Control the flow of traffic within your VPC by defining routes.
Security Groups: Act as virtual firewalls to control inbound and outbound traffic for AWS resources.

3. Virtual Private Cloud (VPC)

A Virtual Private Cloud (VPC) is your isolated network in the AWS cloud. You can define your IP address range, create subnets, and configure route tables.

Note: Every AWS account comes with a default VPC created in each region.

4. Subnets

Subnets are segments of a VPC that allow you to group resources based on security or operational needs. Each subnet resides within a single Availability Zone.


# Example: Creating a subnet using AWS CLI
aws ec2 create-subnet --vpc-id vpc-12345678 --cidr-block 10.0.1.0/24 --availability-zone us-west-2a

5. Route Tables

Route tables contain a set of rules, called routes, that determine where network traffic is directed. Each subnet must be associated with a route table.


# Example: Associating a route table with a subnet
aws ec2 associate-route-table --subnet-id subnet-12345678 --route-table-id rtb-12345678

6. Security Groups

Security groups act as virtual firewalls for your instances to control inbound and outbound traffic. You can define rules based on IP protocol, port number, and source/destination IP address.


# Example: Creating a security group
aws ec2 create-security-group --group-name MySecurityGroup --description "My security group" --vpc-id vpc-12345678

7. Best Practices

Design your VPC layout before creating resources.
Use multiple subnets for better resource organization and availability.
Implement security groups and network ACLs for a layered security approach.
Regularly review and update your route tables and security rules.
Monitor network traffic using AWS CloudWatch and VPC Flow Logs.

8. FAQ

What is a VPC?

A VPC is a virtual network dedicated to your AWS account, providing you complete control over your networking environment.

Can I have multiple VPCs in one AWS account?

Yes, you can create multiple VPCs in a single AWS account, allowing for isolation and organization of resources.

What is the difference between a security group and a network ACL?

Security groups operate at the instance level and are stateful, while network ACLs operate at the subnet level and are stateless.