Differences Between Windows and SQL Server Authentication

Authentication is a crucial aspect of any security strategy. It is a process or act of proving that a specific person’s identity is true, valid, or genuine. To put it simply, it is an act of determining whether someone or something is what it actually claims to be.

When it comes to Microsoft SQL Server, there are two different modes of authentication, namely Windows mode and mixed mode. These two modes determine how the system authenticates or identifies a particular user. 

If you choose Windows authentication mode, it actually disables the SQL authentication mode and permits Windows authentication mode. On the other hand, if you select the mixed authentication mode, it allows both Windows and SQL Server authentication modes. This is because there is no way to disable the Windows authentication mode. It always remains active. 

In this blog post, we shall discuss how Windows authentication mode and SQL Server authentication mode differ from each other. But first, let us understand what these authentication modes exactly mean. 

So, let us begin our discussion!

What Is Windows Authentication Mode? 

When you choose Windows authentication mode for MS SQL Server, you have to provide the login credentials of the Windows account to access the database server. Basically, this mode does not authenticate users based on the SQL specific-login credentials. Instead, it verifies the user’s identity based on their Windows account. 

The primary idea behind this mode is that first, you need to authenticate yourself within Active Directory. Later, SQL Server authenticates your identity through the Windows principal token in the OS. 

Moreover, in this authentication mode, SQL Server depends on Windows for user authentication. So, it is also sometimes known as integrated security. 

When you connect to SQL Server using Windows authentication mode, SQL Server does not validate your identity. Instead, Windows does it all because it is the default authentication mode. In addition, this mode is more secure than SQL Server authentication mode. 

Pros 

• Windows authentication mode leverages the Kerberos authentication protocol. Therefore, it is a secure approach to connecting to SQL Server. It leverages token and service principal name (SPN) for validating a user’s identity. 

• This mode does not transmit your password across the network. As a result, it protects your password from getting stolen. 

• When using this mode, SQL Server does not store your login credentials. 

• Since this mode leverages Kerberos security protocol, you can implement various password policies, including password expiration, account lockouts, and complex passwords. 

Cons

• When you choose Windows authentication mode for connecting to SQL Server, all the users have to be part of the Active Directory. 

• Database administrators do not have any control over the Active Directory logins. 

What Is SQL Server Authentication Mode? 

In SQL Server authentication mode, the username and password are created in SQL Server and are not based on a Windows account. When you use this authentication mode, you create a different username and password and store it in SQL Server. 

Whenever you need to connect to SQL Server, you have to provide the login credentials stored in SQL Server. There is nothing to do with the Windows account’s credentials. Also, it is important to note that you must set a strong username and password for your SQL Server account. 

For SQL Server logins, there are three optional password policies available, as follows: 

• The user should change the password every next time it connects to SQL Server. 

• You can also enforce the password expiration policy, where you need to change the password when it expires after a certain age. 

• The third option is to enforce the Windows login policy for SQL Server login. It entails lengthy passwords and complexity. 

Pros 

• This mode enables SQL Server to support older and third-party applications that require SQL Server authentication. 

• It lets SQL Server support environments with mixed operating systems. 

• This mode enables any users to connect to SQL Server. 

• SQL Server supports websites and lets users create their own identities. 

Cons

• Every time you want to connect to SQL Server, you need to provide the login credentials. 

• You need to remember the username and password. If you have multiple SQL Server instances, it becomes challenging to remember all those credentials.

•  There are chances that hackers may steal your credentials as they are stored in the master database in an encrypted form. 

• This mode does not use the Kerberos security protocol. 

Windows Authentication Mode vs. SQL Server Authentication Mode

The following table highlights the differences between Windows authentication mode and SQL Server authentication mode: 

Conclusion

This brings us to the end of our discussion on the differences between Windows and SQL Server authentication modes. In Windows authentication mode, you can connect to SQL Server through a Windows account. On the other hand, SQL Server authentication mode requires you to create a new username and password that gets stored in SQL Server. As Windows authentication mode supports Kerberos protocol, it is more secure than SQL Server authentication mode.