Divya's Blog

Windows authentication and IIS

 windows authentication for ASP.NET application, need to configure authentication within IIS. This is because IIS provides Windows authentication.

IIS provides four different authentication methods:

1. Anonymous
2. Basic
3. Digest and
4. Windows integrated

• IIS doesn’t perform any authentication for  the anonymous authentication ie it allows any one to access the ASP.NET application.
• In the  basic authentication, users must provide a windows username and password to connect. How ever this information is sent over the network in clear text, which makes basic authentication very much insecure over the internet.
• In the digest authentication, users must still provide a windows user name and password to connect. However the password is hashed before it is sent across the network.
• Digest authentication requires that all users be running Internet Explorer 5 or later and that windows accounts to stored in active directory.

Windows integrated authentication:

• In windows integrated authentication, passwords never cross the network.
• Users must still have a username and password, but the application uses either the Kerberos or challenge/response protocols authenticate the user.
• Windows-integrated authentication requires that all users be running internet explorer 3.01 or later Kerberos is a network authentication protocol.
• It is designed to provide strong authentication for client/server applications by using secret-key cryptography.
• Kerberos is a solution to network security problems. It provides the tools of authentication and strong cryptography over the network to help to secure information in systems across entire enterprise

Passport authentication

• Passport authentication  make  use  of Microsoft’s passport service to authenticate users of your application.
• If  users have signed up with passport and we configure the authentication mode of the application to the passport authentication, all authentication duties are off-loaded to the passport servers.
•  Passport uses an encrypted cookie mechanism to indicate authenticated users. If users have already signed into passport when they visit our site, they’ll be considered authenticated by ASP.NET. Otherwise they’ll be redirected to the passport servers to log in. When they are successfully log in, they’ll be redirected back to your site
• To use passport authentication we have to download the Passport Software Development Kit (SDK) and install it on our server.

The SDK can be found at http://msdn.microsoft.com/library/default.asp?url=/downloads/list/websrvpass.aps. It includes full details of implementing passport authentication in your own applications.

Forms authentication

• Forms authentication provides us with a way to handle authentication using our own custom logic with in an ASP.NET application.

The following applies if we choose forms authentication.

•  When a user requests a page for the application, ASP.NET checks for the presence of a special session cookie. If the cookie is present, ASP.NET assumes the user is authenticated and processes the request.
• If the cookie isn’t present, ASP.NET redirects the user to a web form you provider and we may choose any authentication method to check the form
•  When the user is authenticated, you indicate this to ASP.NET by setting a property, which creates the special cookie to handle subsequent requests.