Your question doesn't make a lot of sense as Active Directory does not run on Linux if you have some sort of directory/user service running on Linux it would be something like
OpenLDAP[
^], if you are running Active Directory then that would be a Windows server and as you have an ASP.Net web site which would be running under IIS (Windows Web Sever) you could use
Integrated Authentication[
^], this option is best used on intranet sites not internet sites.
Try the
Novell LDAP Library[
^] it can be downloaded from
here[
^], if you want to connect to an LDAP server yourself.
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