Oracle Database authentication through Active Directory We have Oracle 11g database running on a RHEL 6 server. 
and we have a Active Directory domain running on windows 2008 server in same network. 
I want to authenticate Oracle database users using this AD. 
I searched but found only documents related to kerberos authentication where the database clients directly authenticate with AD and then contact Oracle database. 
I cant use this setup as we don't have any network connection between client softwares like Toad and Active directory. The client softwares run in a different network and not connected to this windows domain.  These clients can only connect to Oracle database.
I want the following setup


User will enter domain user name and password in the client software
The Oracle database server has to pass these details to AD and try to authenticate
Based on AD response, oracle has to allow or block the user


Please let me know if this is possible with my environment. 

Note: the RHEL server on which Oracle is installed is joined to this Widows Domain using SSSD and this OS authentication n works without issues
This is called Enterprise User Security, which is available in Enterprise Edition databases.

You can do this with Oracle Virtual Directory or Oracle Unified Directory (preferred).

They both require the Directory Services Plus licence.

The required steps for this can be found at for example:

Enterprise User Security (EUS) with Active Directory (AD) Integration Using OUD Proxy (Doc ID 1571196.1)

A public walkthrough:

Configure EUS with OUD, AD and DB12c