Configuring and securing connections to Azure SQL Database

With Azure SQL Database, Azure configures the network for you and by default restricts all access using Azure SQL Database firewall rules, as discussed in Chapter 3, “Getting started with an Azure SQL Database.” If a firewall rule does not exist, Azure will reject all connection attempts from IP addresses that have not been whitelisted explicitly.

 Use database-level firewall rules in conjunction with contained users (discussed below) whenever possible to make your database more portable.

 Use server-level firewall rules when you have many databases that have the same access requirements and you don’t want to spend time configuring each database individually.

Additionally, Azure SQL Database requires encrypted connections at all times while data is “in transit” to and from the database. In your application’s connection string, you must specify parameters to encrypt the connection and not to trust the server certificate (this is done for you if you copy your connection string out of the Azure portal). If you do not, the connection will not verify the identity of the server and will be susceptible to “man-in-the-middle” attacks. For the ADO.NET driver, for instance, these connection string parameters are Encrypt=True and TrustServerCertificate=False. For more information, see Azure SQL Database Connection Encryption and Certificate Validation. The code block below shows a sample ADO.NET connection string.

Server=tcp:[your_sql_database_server_name_here].database.windows.net,1433;Database=[your_sql_database_name_here]>;User ID=[your_username_here]@[your_sql_database_server_name_here];Password={your_password_here};Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;

Unlike SQL Server in an Azure virtual machine, with Azure SQL Database you do not have to secure the operating system itself. However, all Azure subscription administrators have access to the SQL Database instance, and you should limit subscription administrators.

Source of Information : Migrating SQL Server Databases to Azure