Elastic IP

Elastic IP (EIP) is a way to use a public IPv4 address that's reachable from the internet. It can be dynamically assigned to an EC2 instance, network interface, or other resources. A few characteristics of Elastic IP are as follows: 

• The Elastic IP is associated with the account and is region-specific. For example, the EIP in us-east-1 can only be associated with resources in us-east-1.
• You can disassociate an Elastic IP from a resource, and re-associate it with a different resource. This flexibility can sometimes be used to ensure high availability. For example, you can migrate from a smaller EC2 instance to a larger EC2 instance by reassigning the same IP address from the small EC2 instance to the larger one.
• There is a small hourly charge associated with Elastic IP.

You can request Elastic IP from the portal. After assignment, you can associate it with the desired resources:

In the coming section, we will look at how we can use the NAT Gateway to allow communication for the private subnets to the internet.