c# - How to check if currently logged in user exists in Active Directory -

we have web application ldap/active directory authentication in place.

now requirement if user, exists in active directory, logged in machine , accesses web application, doesn't require authentication. directly authenticated , landed website's landing page.

could please guide if have idea/hint/ref/solution?

thank much.

first need change authentication "windows" , force website users enter windows credential , can validate on page load

1) enable windows authentication in iis , disable anonymous authentication more information see article : windows authenticaition asp.net

2) on page load identify identity of user using page.user.identity

3) query ldap through using system.directoryservices , using system.directoryservices.activedirectory check if user exist or not

for more detailed info on ad useful article almost ad