AWS VPC

Every IP has network ID and host ID. Depends on the subnet mask.

example: 192.168.0.0/24 This means the first 24 bits from the left is the network ID (fixed for all hosts) and the last 8 bits can be the host ID.

CIDR (Classless interdomain routing) We use CIDR if we want non-standard or classless IP range and subnet mask. Using variable length subnet masks.

VPC

VPC is a logically isolated portion of the AWS cloud within a region.

Can deploy application in different availability zones. Subnets are created within AZs.

VPC router takes care of routing within the VPC and outside of the VPC (using route tables).

• CIDR block size can be between /16 to /28
• CIDR block must not overlap with any existing CIDR block that’s associated with the VPC

Network ACL checks for inbound and outbound, compared to security group where it allows outbound traffic automatically.

NAT gateway is only required for private subnets to access internet.