An Amazon Web Services Elastic IP is essentially an IP address that is tied to your AWS account. It’s not specifically tied to any given EC2 instance and can be used for multiple instances.

When you launch your first EC2 instance you’re immediately assigned a Public IP address. This IP address is not permanent and if you restart your instance for any reason, a memory leak, hardware failure or anything else, that IP address will be dropped from your account and you’ll be assigned a new one.

This won’t do you much good if you want your site to be consistently accessible from the same address. That’s where the Elastic IP’s come in.

An Elastic IP is a permanent IP address that is tied to your AWS account. That means that you can start and stop as many EC2 instances as you want, that IP address will remain constant.

One thing to note, if you have an Elastic IP address in your account and you do not have it assigned to an EC2 instance, you will be charged for it. If you are using the IP you will not be charged.

Setting up an Elastic IP

Assuming you have an AWS Instance already created:

  1. Log into your AWS EC2 Management Console.
  2. In the left hand menu under Network & Security select ‘Elastic IPs.’
  3. Select ‘Allocate New IP Address’ and follow the prompt.
  4. Once you’ve allocated an IP address, in the left hand menu of the Management Console navigate to ‘Instances.’
  5. Right click on the instance you’d like to edit and select ‘Networking > Associate Elastic IP Address’ and choose the IP address you just created.

Congratulations! If all went well your instance will now be accessible from the static IP address. This will not change when the server reboots so you’ll be able to log in and manage your server much more reliably.