AWS Associate Architect Certification Lecture 16 — Virtual private cloud Theory Part 2

Hi All,

Lets explore VPC more in this lecture,

VPC types:
1. Default VPC — in every region , we can use default VPC.
2. Custom VPC — You can customize the vpc according to your requirement.

What is Default VPC?
1. Created in each AWS region when AWS account is created.
2. Has default CIDR, security groups, NACL and route table settings.
3. Has an Internet gateway by default present.

What is Custom VPC?
1. It’s a VPC on AWS account owner creates.
2. AWS user creating the custom VPC can decide the CIDR.
3. Has its own default security group, Network ACL and route table;
4. Does not have Internet Gateway by default, One needs to be created if needed.

To create VPC , you need to do following 4 things in sequence :
1. Create VPC.
2. Create subnet.
3. Create Internet gateway.
4. create route table.

How to create public subnet and private subnet?

Public Subnet —
1. If subnet traffic is routed to an Internet gateway, the subnet is known as Public subnet .
2. If you want to communicate with the Internet IPv4, It must have a public IPv4 address, or an elastic IP address.

Private Subnet —
1. if a subnet does not have a route to the internet gateway, the subnet is known as a Private subnet.
2. When you create a VPC, you must specify an IPv4 CIDR block for the VPC.
3. The allowed block size is between /16 to /28 network.
4. The first 4 and last IP address of subnet can not be assigned.
5. following IP addresses are reserved.
10.0.0.0 — network address.
10.0.0.1 — Reserved by AWS for the VPC route.
10.0.0.2 — Reserved by AWS . The IP address of DNS server.
10.0.0.3 — for future use.
10.0.0.255 — broadcast address.

/24 means 32–24 = 8 , so 2⁸ = 256 total but remove the reserved address , so 256–5 = 251 addresses are allowed.