There are two security modes (authentication modes) in SQL Server 7.0:
Windows NT Authentication
The security mode is selected during SQL Server 7.0 installation and can
be modified at any time.
To change the security modes, you can do the following:
Click Start, Programs, Microsoft SQL Server 7.0 and click
SQL Enterprise Manager to run SQL Enterprise Manager from the
Microsoft SQL Server 7.0 program group.
Select the server you want to work with, then from the Tools menu
select SQL Server Configuration Properties, and choose the Security
Set SQL Server 7.0 Security Mode
Windows NT Authentication
When it is used, then Windows NT is responsible for managing user
connections through its Access Control List (ACL). So the advantage
of using Windows NT Authentication is single-password access to all
resources on a Windows NT domain, and password aging, and encryption
across the network. Windows NT security also provides auditing,
minimum password length, and account lockout after multiple invalid
If Windows NT Authentication Mode is used, and a user attempts to
connect to SQL Server providing nonblank login name, then the login
will be ignored.
With Windows NT Authentication, only Multi-Protocol and Named Pipes
clients are supported, and only trusted connections are allowed
into SQL Server (trusted connections are only available via the
Multi-Protocol or the Named Pipes).
This security mode is used by default, but Windows NT Authentication
is not available, when SQL Server is running on Windows 95/98.
Mixed Security allows users to connect using Windows NT Authentication
or using SQL Server Authentication.
Mainly, SQL Server Authentication is provided for backward compatibility,
but is also required when SQL Server is running on Windows 95/98 because
Windows NT Authentication Mode is not supported on Windows 95/98.
When SQL Server Authentication is used, SQL Server manages its own
login validation process for all connections, i.e. SQL Server
is wholly responsible for authenticating a user and for enforcing
password and login restrictions.
You should choose Mixed Security Mode, when SQL Server running on
Windows 95/98, or for connections with internet and clients other
than Windows NT clients.
In this case, when a user connects to a SQL Server, then SQL Server
checks is it a trusted connection or not (checks is the login name
matches the user's network username, or if the login name is null).
If it is a trusted connection, then SQL Server uses Windows NT
Authentication, if it is not a trusted connection then SQL Server
uses SQL Server Authentication (i.e. tried to find the same SQL Server
login name and password, as user has passed).
See All Articles by Columnist Alexander Chigrik