Get the current user's name and domain.
Get the name and domain of the currently logged in user via the "System Security" namespace and the "Windows Principal" object.

See if a user belongs to a local or global security group.
Use the "IsInRole" function of a "WindowsPrincipal" object to determine if a user belongs to a specific local or global security group.

Programmatically Use Impersonation in ASP.NET.
Learn about IIS and ASP.NET security, the user accounts and groups used during anonymous access, and how impersonation works. See how to impersonate another user's security credentials via the web.config and programmatically though your VB.NET code.