What is the main function of an Elastic network interface?

The main function of an Elastic Network Interface (ENI) is to attach to an instance for connection management. An ENI serves as a virtual network interface that can be associated with an Amazon EC2 instance within a Virtual Private Cloud (VPC). This allows instances to communicate with each other and with other resources on the network.

An ENI can have multiple attributes, including a primary private IPv4 address, one or more secondary private IPv4 addresses, one Elastic IP address, a public IPv4 address, and security groups. By attaching an ENI, you can enhance the networking capabilities of an instance, manage network traffic, and maintain stable IP addresses during instance stops and starts.

This attachment plays a crucial role in connection management by allowing for the separation of network functions from the compute instance itself. For example, an ENI can be detached from one instance and attached to another, providing flexibility and resilience in network architecture.