Understand Elastic IPs

Introduction

The problem with AWS auto-assignment of public IPv4 addresses to EC2 instances is that the IP address is released once the EC2 instance is stopped, and a new public IPv4 address is assigned to it when it is started again. This can be problematic in cases where persistent network communication is required between resources, and it can result in a lot of manual overhead. The above problem is solved by providing access to a static public IPv4 address that does not change and can be reused as needed.

An Elastic IP (EIP) is a static public IPv4 address allocated from a pool of public IPv4 addresses ...