What is the main functionality of Elastic IP addresses?

The main functionality of Elastic IP addresses is to maintain a consistent IP address across virtual machine instances. Elastic IPs are designed to be associated with an account rather than with a specific instance, allowing users to dynamically associate and disassociate the IP address with different instances as needed. This feature is particularly useful in situations like instance failure or scaling, where you might need to switch the IP address to another instance while still maintaining the same public-facing address. This seamless reassignment helps ensure that external clients can reliably connect to the service without needing to track any changes to the underlying infrastructure.

Other options, while relevant to cloud functionalities, do not pertain to the specific role of Elastic IPs. Static DNS services, for example, involve translating domain names to IP addresses and are separate from how Elastic IPs function. Data privacy across networks involves encryption and secure data handling practices, which are not related to IP address management. Serverless computing pertains to a different architectural paradigm that allows users to run code without provisioning or managing servers, separate from the management of Elastic IP addresses.