A Static IPv4 address more suited for dynamic cloud computing is called an Elastic IP (EIP) address. The address is mapped to another instance that is as soon as feasible made available in your account in order to accomplish this.
Elastic Pricing for IP Addresses
- AWS applies a small hourly charge to ensure Elastic IP addresses are used efficiently.
- Charges apply if multiple Elastic IPs are assigned to the same instance.
- You are billed when an Elastic IP is not attached to a running instance (instance stopped/terminated or ENI not associated).
- AWS also charges if an Elastic IP is remapped more than 100 times in a month.
- AWS charges for Elastic IP addresses regardless of attachment status, to encourage IPv4 conservation; unused Elastic IPs cost $0.005 per hour, encouraging users to release unused addresses.
Elastic IP Addresses and the AWS Network's Reach
- AWS network scope basically complies with AWS's geographical boundaries. The public IP addresses allocated to your instance vary by area, but they are universal in nature, which means that, like all public IP addresses, they are all distinct and may be accessed by anybody worldwide.
- For instance, if you start an instance in the AWS US East region, it will have a public IP address that comes from one of the IP address ranges that Amazon keeps for US East. With that public IP address, your instance is accessible to all resources in the world (including those in AWS).
- Region-scoped IP addresses are also available. Five Elastic IP addresses are the maximum you can have per area by default, and they are all contained within the region-specific address ranges.
- Region-scoped IP addresses also apply to private ones. Using the private IP address assigned to the instances, instances inside any availability zone in a given region can connect with one another without being charged for network traffic.
Working of AWS Elastic IP
The working of AWS Elastic IP can be explained in the following manner:
1. Allocate an Elastic IP Address: It is easy to assign an IP address to your account. Your IP address may be assigned using either the pool of IP addresses offered by Amazon or the private IP address pool you have added to your account.
There are the following options for the Public IPv4 address pool:
- IPv4 Addresses are available on Amazon: If you want an IPv4 address assigned from the pool of IPv4 numbers maintained by Amazon.
- My Collection of Open IPv4 Addresses: If you wish to assign an IPv4 address from a pool of IP addresses you've added to your AWS account. If your network does not contain any IP address pools, this option is disabled.
- The IPv4 Address Pool that belongs to the Customer: If you need to distribute an IPv4 address for use with AWS Outposts from a pool made using your on-premises network. If you don't have AWS Outposts, this option isn't available to you.
2. Describe your Elastic IP Address:View Elastic IP metadata in the EC2 console or via AWS CLI/API. Here the metadata includes the name, descriptions and other necessary details.
3. Tag an Elastic IP Address: You can use tags to distinguish between your IP addresses in case you have created multiple IP addresses.
4. Connect or Disconnect an Elastic IP address from a Network Interface or Instance
5. Release an Elastic IP Address: We advise releasing an Elastic IP address via one of the following procedures if you no longer require it. The IP that needs to be released cannot currently be connected to any EC2 instance, NAT gateway, or Network Load Balancer on AWS.
Features of AWS Elastic IP
- Elastic IPs are static public IPv4 addresses that do not change over time and remain assigned to your AWS account until you explicitly release them.
- An Elastic IP is associated with a network interface (ENI); attaching it to an instance effectively attaches it to the instance’s primary network interface.
- When an Elastic IP is associated, it replaces any existing public IPv4 address, and the instance’s public DNS name updates to reflect the Elastic IP.
- Unlike regular public IPv4 addresses, Elastic IPs can be detached and reassigned to another instance, allowing connections to resume quickly after failures or maintenance.
- Elastic IPs come from either AWS’s public IPv4 pool or your own custom IP pool; IPs from your own pool do not count against Elastic IP limits.
- Elastic IPs are region- and network-border-group specific, cannot be moved across regions, and can be used with EC2 (in a VPC) and services like ELB, CloudFront, and Elastic Beanstalk.
- Elastic IPs are free while attached to a running instance, incur a small hourly charge when unused, and can support high availability by quickly switching the IP between instances.
Limitation of Elastic IP
Elastic IP is easy to use, but it has several drawbacks.
- AWS sets a default restriction of five Elastic IP addresses per region.
- AWS recommends using private IPs for internal communication and Elastic IPs only for public access or failover.
- AWS charges an hourly fee for Elastic IP addresses that are not associated with a running instance. This can make it expensive to reserve IP addresses that are not being actively used.
- The number of Elastic IP addresses that you can allocate per account is limited by default. AWS imposes a soft limit of 5 Elastic IP addresses per region for each account. If you need more than this, you will need to request a higher limit from AWS support.
- Public IPv4 addresses are a limited resource on the internet, and there is a finite number of them available. This means that it's important to use Elastic IP addresses judiciously and only allocate them when they are truly needed.
- Elastic IP addresses can only be used in the same AWS region where they were allocated. This means that if you need to move an instance to a different region, you will need to release the existing Elastic IP address and allocate a new one in the new region.