How to access FormsAuthentication section from Code behind in ASP.NET?

To access the properties and modify the properties of FormsAuthentication from code behind, use following code snippet.

// Get the Web application configuration.
System.Configuration.Configuration configuration = 
    WebConfigurationManager.OpenWebConfiguration("/aspnetTest");

// Get the external Authentication section.
AuthenticationSection authenticationSection = 
    (AuthenticationSection)configuration.GetSection(
    "system.web/authentication");

// Get the external Forms section .
FormsAuthenticationConfiguration formsAuthentication =
    authenticationSection.Forms;