What are Azure database Firewall rules used for?

Azure database Firewall rules are specifically designed to control and manage access to Azure SQL Database. These rules accomplish this by allowing you to specify IP address ranges from which connections are permitted. This means that users connecting to the Azure SQL Database must originate their requests from an allowed IP address; otherwise, they will be blocked from accessing the database.

This feature serves a crucial role in securing the database by ensuring that only specified clients or networks can communicate with the database instance. Consequently, it helps mitigate the risk of unauthorized access and potential security breaches.

The other options pertain to different aspects of database management that do not involve access control through IP restrictions. For instance, restoring databases from backups relates to data recovery processes, encrypting data at rest is focused on data security within the storage layer, and optimizing query performance involves improving the efficiency of database operations. Each of these functions is essential in its own right but does not directly address the access control mechanisms that firewall rules are designed to implement.