Why Does an AWS ALB Have an Elastic IP and Others Don't? Authorization Issues

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Many internet-facing Application Load Balancers (ALBs) in AWS will automatically have public IPv4 addresses assigned to them by the service. These addresses are managed by AWS and come from the pool of public IPs associated with EC2. In your AWS account, these IPs appear as Elastic IPs (EIPs) with a special attribute indicating they are service-managed, often labeled as “ALB.”

Here’s what you need to know about these IPs:

First, these Elastic IPs are fully managed by the ALB service itself. This means you can’t manually modify or release them. If you try to delete or disassociate them, you’ll encounter permission errors because AWS controls these IP addresses automatically.

Second, if you see such an Elastic IP on one ALB but not on others, it could be because that particular ALB is internet-facing. Internal ALBs typically don’t have public IPs assigned in this way. Also, since early 2024, AWS has been making these service-managed IPs more visible in customer accounts, especially after introducing charges for public IPv4 addresses.

Third, this behavior is not a mistake or misconfiguration. The ALB service handles these IP addresses on your behalf and will release them back into the public pool once they’re no longer needed. If you want to stop using the ALB and release these Elastic IPs, you should simply delete the ALB itself. Once the load balancer has been removed, AWS will automatically free up those IPs.

If you need a fixed IP address for your ALB—perhaps for whitelisting purposes—the best solution is to place a Network Load Balancer (NLB) in front of your ALB. NLBs support static Elastic IP addresses that you can assign and control directly.

For further details, check out the AWS documentation on Application Load Balancers and AWS re:Post discussions about Elastic IPs created by ALBs.