There are three types of authentication available in ASP.NET:
- Windows Authentication: This authentication method uses built-in Windows security features to authenticate a user.
- Forms Authentication: Authenticates against a customized list of users or users in a database.
- Passport Authentication: Validates against Microsoft Passport service which is basically a centralized authentication service.
In ASP.NET, there are primarily three types of authentication mechanisms:
- Windows Authentication: This method relies on Windows accounts for authenticating users. Users’ credentials are verified against the Windows user database. It’s suitable for intranet applications where both the server and clients are part of the same Windows domain.
- Forms Authentication: This method involves creating a custom HTML login form where users provide their credentials (username and password). Upon successful authentication, ASP.NET issues a cookie to the client, which is then used for subsequent requests. This method is suitable for internet-facing applications where users don’t necessarily have Windows accounts.
- Passport Authentication (deprecated): This method was used in earlier versions of ASP.NET. It involved authentication through Microsoft’s centralized authentication service called Passport. However, as of .NET Core, Passport authentication has been deprecated in favor of other authentication mechanisms.
When answering an interview question about authentication in ASP.NET, you should provide a brief explanation of each type, highlighting their use cases and differences. Additionally, it’s important to mention any changes or deprecations, such as the deprecation of Passport authentication in newer versions of ASP.NET.