Interact with Default VPC

Amazon default VPC

Every AWS account comes preconfigured with a default VPC created by AWS in every AWS Region. A default VPC comes with the default configuration, which is the same for every AWS account. There can only be one default VPC per Region, and we can delete it and create it again. When recreated, the default VPC configuration remains the same as any other default VPC.

Each default VPC is created with the same IPv4 CIDR range, 172.31.0.0/16, giving the VPC a total of 65536 IPv4 addresses. Furthermore, the default VPC is preconfigured with a default public subnet in each AWS Region availability zone. The subnet’s netmask is /20 from the VPC network block, which provides 4096 IP addresses per subnet, with a few IP addresses reserved by AWS.

For example, if we look at the default VPC in the eu-west-1 (Ireland) AWS Region, we’ll notice three public subnets with /20 CIDR because eu-west-1 contains three availability zones, eu-west-1a, eu-west-1b, and eu-west-1c.