Amimoto AMI High Performance WordPress Cloud Hosting services run on Amazon Web Services environment.
There you’ll see that once you get an Amimoto AMI instance, you’ll have a public IP, and even have the option to associate an Elastic IP (EIP).
In some of our documentation and tutorials, we show how to associate an EIP to your instance.
At times, like in our meetups or hands-on events, we receive questions like: “What’s the difference between Public IP and Elastic IP?” So we’ve decided to create Public IP vs. Elastic IP: The Ultimate Showdown for additional guide.
Public IP ADDRESS
- Public IP address is reachable from the internet. From the pool of IP addresses, this is assigned to your instance, and is not associated with your AWS account.
- Through NAT, or Network Address Translation, your Public IP is mapped to the primary private IP address.
- You use your Public IP for communication between your instances and for internet communication.
- Every instance that gets a public IP also gets an external DNS hostname.
- Public IP cannot be manually associated or disassociated from your instance.
- Default: Ec2-Classic Amimoto AMI instance gets 2 IP addresses: Private and Public IP at launch.
- In EC2-Classic, your instance automatically acquires a Public IP. This automatic assignment may not be modified.
- The Public IP in your EC2-Classic will be mapped to the private IP via network address translation (NAT).
- Once you’ve disassociated the Public IP from your Amimoto AMI instance, it may not be used again.
- Another characteristic of EC2-Classic is it’s associated to your Amimoto AMI instance, not to your AWS account.
- By default, EC2-VPC Amimoto AMI instances launched in non-default subnet, do not automatically receive a Public IP address.
- The attribute of your subnet will determine if your instances launched into that subnet will get a Public IP.
- You may change your subnet’s Public IP.
- At launch, you may enable or disable the public IP addressing function.
- If a Public IP is released from your Amimoto AMI instance, it will not receive a new one if there’s more than one network interface attached to the instance.
- Just like EC2-Classic, your Public IP is mapped to the Private IP via NAT.
- The Public IP is associated to your Amimoto AMI instance, not your AWS account.
- Once disassociated, you cannot reuse the Public IP again.
When is Public IP Released?
- Your Public IP is released when you stop or terminate your instance.
- The moment an Elastic IP is associated to the instance
- (EC2-VPC): your Public IP is released when an EIP is associated to the primary network interface (eth0) of your instance
- You cannot reuse your Public IP once it’s disassociated from the instance.
- The Public IP gets back to the address pool.
- When you restart an instance, it gets a new Public IP.
If your Amimoto AMI instance is in a different availability zone and you’re using Public or EIP address, then Regional Data Transfer fees will apply.
Regardless of the instance’s availability zone, if you use Public or EIP address, you will be charged for the Regional Data Transfer cost.
When a dynamic DNS is used to map a DNS name that’s already existing, the IP will take 24 hours to propagate through the internet. As a result, your new instances might not receive traffic, but the terminated instances will. The solution for this is Elastic IP.
Elastic IP Address
- Your Elastic IP address is a Public IP that you may allocate to your account. This may be associated to and from your Amimoto AMI instances as necessary.
- An EIP is allocated to your account unless you release it.
- It takes several minutes to remap an EIP.
- It’s not required to have EIP in all your instances.
- Reverse DNS record may be configured.
- You are limited to 5 EIPs per region, but if you wish to have more, you may apply and AWS will look over your case.
- When you associate an EIP to your Amimoto AMI instance, the current IP of your instance will be released back to the address pool.
- When an EIP is disassociated from the instance, in a few minutes, the instance gets a new public IP.
- If you stop the instance, your EIP is disassociated from it.
- You get charged by the hour for every EIP that is not associated with a running instance (rates vary on AWS Region).
- However, you don’t get billed for an EIP that is associated to your Amimoto AMI instance.
- Additional EIP: not available for EC2 Classic.
- Your Amimoto AMI instance in Virtual Private Cloud (VPC) will receive a DNS hostname if you have enabled your DNS hostname.
- It is possible to acquire multiple EIPs in EC2-VPC unlike Classic.
- If you want additional EIP for your instance, please note that this is charged per hour (pro rata) and rates vary on AWS Region.
- Every EIP in a non-default VPC has a private IP assignment, unless there was a specific public IP request upon launch or the public IP subnet was modified.
In a non-default VPC, to make sure Amimoto AMI instance (without public IP assignment) is able to communicate with the internet, EIP must be allocated to use with VPC, then it must be associated to elastic network interface (ENI) that is attached to the instance.
- In default VPC, once you’ve associated EIP to an instance, the Public IP is released.
- When you disassociate your EIP from Amimoto AMI, it gets a new Public IP in a few minutes.
- If you have attached a second network interface to your instance, it will not automatically get a new Public IP. Instead, an EIP has to be manually associated to it.
- If you choose to launch your Amimoto AMI with EC2-VPC, you can assign a static private IP that persists across starts and stops.
- With this type of instance, you may set the conditions of your network interfaces.
- Amimoto AMI may also have several network interfaces attached to it.
- Your EIP in EC2-VPC is always associated to your instance until it is stopped. And it has to be released manually.
An EIP that is associated with a running Amimoto AMI instance is NOT charged, except for additional EIPs associated to the instance.
- Even though your Amimoto AMI is running, you may change the security group membership of your instance.
- With EC2-VPC, Amimoto AMI instance may run on single-tenant hardware.
- You can also have additional layers of access control through network access control lists (ACL) for your instances.
- The outbound traffic (egress filtering) and inbound traffic (ingress filtering) may be controlled from your Amimoto AMI instances.
- Sometimes you might need a persistent Public IP; something that you can associate to and from your Amimoto AMI instances as needed. For this, we recommend the usage of Elastic IP address. You may allocate your own EIP, and associate it with your instance.
You get charged per hour for every EIP that is not associated with a running instance. Additionally, you are billed for an EIP that is associated with an unattached network interface. Make sure you release your EIP afterwards.
|EC2-Classic||Public IP||Elastic IP|
|What happens when the instance is stopped?||The Public IP will be released, and it gets a new IP after restarting the instance.||Disassociated from the instance.|
|Fees||Hourly charge fees apply for every EIP not attached to a running instance.No charge for an EIP associated with the running instance.|
|Multiple Address||Single private IP and one EIP only.Multiple EIP is not supported for EC2-Classic Amimoto AMI instances.|
|EC2-VPC||PUBLIC IP||ELASTIC IP|
|Released when||an EIP is associated to the primary network interface (eth0) of your instance.||You have to manually disassociate the EIP from the Amimoto AMI instance. After that, it gets a new Public IP in a few minutes.|
|Reassociation||May not be used again once disassociated from your instance.||For EC2-VPC only account: association of an EIP that’s already with another instance makes your new instance receive the address automatically.|
|What happens when the instance is stopped?||If you have attached a second network interface to your instance, it will not automatically get a new Public IP. Instead, an EIP has to be manually associated to it.||The EIP is still associated.|