VPC is something you should know in-depth for AWS Certified Solution Architect Associate Exam & AWS Certified SysOps Exams.

At the poit of AWS Certified cloud practitioner level, you should know about:

• VPC, Subnet, Internet Gateways, NAT Gateways
• Security Groups, Network Gateways, VPC Flow Logs,
• VPC Peering & VPC Endpoints
• Site to Site VPN & Direct Connect
• Transit Gateways. which will be covered in this blogpost.

• Public IPv4 - can be used on the Internet.
• EC2 instance gets a new PublicIP every time you stop and start it (default behaviour)
• Private IPv4 - can be used on private network(LAN) such as internal AWS Server/Networking.
• Private IPv4 is fixed for EC2 instance even if you start or stop them.

• Every IP is public

It allows you to attach a fixed public IPv4 address to an EC2 instance. Note: It has ongoing cost if not attached to EC2 instance or if the EC2 instance is stopped!

VPC = Virtual Private Cloud Private Network to deploy your resources (regional AWS Service)

Subnet Allows you to partition of your network inside your VPC (AZ Resources) There are 2 types of subnets:

Public Subnet = It is a subnet that is accessible from the internet

Private Subnet = It is a subnet that is not accessible from the internet

To define access to the internet and between subnets we use route table.

• Internet Gateway helps our VPC instance connect with the Internet.
• Public Subnet have a route to internet gateway.
• NAT gateways (AWS Managed) & NAT Instances (Self Managed) allow your instances in your private subnet to access internet while remaining private.