AWS supports dynamically removing and adding auto assigned public IPv4 address

Amazon VPC announces a network interface setting to dynamically remove and add an [auto assigned public IPv4 address](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-instance-addressing.html#concepts-public-addresses) on EC2 instances. With this capability, customers that no longer require an auto assigned public IPv4 address on their EC2 instance can remove the public IPv4 address, and if needed attach back a new public IPv4 address, by modifying the public IP setting on the network interface. Before today, once a public IPv4 address was auto assigned to EC2 instance it was not possible to remove it. It remained on the network interface for the lifetime of the EC2 instance. The public IP setting on the network interface makes it easier for customers to be public IPv4 efficient and reduce public IPv4 cost. Customers that no longer need the auto assigned public IPv4 or are migrating to using private IPv4 address for SSH using [EC2 instance connect endpoint](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/connect-using-eice.html) can simply remove the auto assigned public IPv4 address, instead of recreating their applications on a new EC2 instance with no auto assigned public IPv4 address. This feature is available in all AWS commercial and the AWS GovCloud (US) Regions at no additional cost. For more information, please visit the VPC [user guide](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-eni.html#working-with-enis).