Exploring AWS !!

Day 18:

Types of VPC, Subnets and Security

Types of VPCs: Default and Non-Default

Default VPC: EC2-VPC platform only — it comes with a default VPC that has a default subnet in each availability zone. A default VPC has benefits of advanced features provided by EC2-VPC and is ready for you to use.

Non-Default VPC: Regardless of which platforms your account supports, you can create your own VPC, and configure it as you need. Subnets created here are called non-default subnets.

Subnets: dividing a large network into multiple smaller logical networks. Each subnet is a separate network on its own machine in one subnet cannot talk to machine in other subnet directly. Route through main router has to be taken.

Types: Public and Private subnets
Public subnet has Internet gateway associated with it.
Private subnet does not have any route to Internet Gateway.

200 subnets can be created per VPC.
5 VPC per region can be created.

Security in VPC:
Security Groups: acts as a virtual firewall for your instances to control inbound and outbound traffic.
Network Access Control Lists (NACLs): optional level of security for VPC that acts as a firewall. Controls traffic in and out of one or more subnets.
Security groups can be used for EC2, while NACLs are for subnets and for one subnet it will give security to 100s of EC2 inside that subnet.