How to: Change Server Authentication Mode

During installation, SQL Server Database Engine is set to either Windows Authentication mode or SQL Server and Windows Authentication mode. This topic describes how to change the security mode after installation.

If Windows Authentication mode is selected during installation, the sa login is disabled. If you later change authentication mode to SQL Server and Windows Authentication mode, the sa login remains disabled. To enable the sa login, use the ALTER LOGIN statement.

Security Note:
It is very important to choose a strong password for the sa login.

The sa login can only connect to the server using SQL Server Authentication.

To change security authentication mode

1. In SQL Server Management Studio Object Explorer, right-click the server, and then click Properties.

2. On the Security page, under Server authentication, select the new server authentication mode, and then click OK.

3. In the SQL Server Management Studio dialog box, click OK, to acknowledge the need to restart SQL Server.

To restart SQL Server from SQL Server Management Studio

1. In Object Explorer, right-click your server, and then click Restart. If SQL Server Agent is running, it must also be restarted.

To enable the sa login by using Transact-SQL

1. Execute the following statements to enable the sa password and assign a password.

   ALTER LOGIN sa ENABLE ;
   GO
   ALTER LOGIN sa WITH PASSWORD = '<password>' ;
   GO
   

To enable the sa login by using Management Studio

1. In Object Explorer, expand Security, expand Logins, right-click sa, and then click Properties.

2. On the General page, you may have to create and confirm a password for the sa login.

3. On the Status page, in the Login section, click Enabled, and then click OK.

See Also

Other Resources

Strong Passwords
Authentication Mode
Security Considerations for a SQL Server Installation
ALTER LOGIN (Transact-SQL)

Help and Information

Getting SQL Server 2005 Assistance