There are two security modes (authentication modes) in SQL Server 7.0:

• Windows NT Authentication
• Mixed

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

page.

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

login requests.

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 Mode

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).