VPC networking components

A VPC network consists of certain components. We will now look briefly at these components.

ENI

ENI stands for Elastic Network Interface and is a virtual network interface. It is a communication hub for an EC2 instance that enables network communication on an instance. An EC2 instance can have one or more network interfaces. When any EC2 instance is created inside a VPC, a network interface is also created by default and attached to it. The default network interface created while launching an instance is called a primary network interface of the instance. This primary network interface also gets one primary IPv4 address from the subnet's available IP range.

You cannot detach a primary network...