I have Domain Controller running on Windows 2008 R2, then I have PFSense as Firewall and Proxy. All User Access Internet use Proxy, then I want Authentication User Proxy from Domain Controller. Below configuration from PFSense to get Authentication User from Active Directory Windows.
1. Authentication for User
Authentication Method : LDAP
Authentication Server : IP Server
Authentication server port : 389
LDAP Version : 3
LDAP Server User DN : CN=Administrator,CN=Users,DC=simasre,DC=local
LDAP Base Domain : DC=simasre,DC=local
LDAP Username DN Attribute : sAMAccountName
LDAP Search Filter : (sAMAccountName=%s)
2. Authentication for Group
Authentication Method : LDAP
Authentication Server : IP Server
Authentication server port : 389
LDAP Version : 3
LDAP Server User DN : CN=Administrator,CN=Users,DC=simasre,DC=local
LDAP Base Domain : DC=simasre,DC=local
LDAP Username DN Attribute : sAMAccountName
LDAP Search Filter : (&(memberOf=CN=Internet-Access,OU=Group-Internet,DC=simasre,DC=local)(sAMAccountName=%s))
Note: browser must setting proxy manual.
CMIIW, Thanks 
Hello, thanks for the post.
I’m trying to do the same but when I enter to the browser and it asks for the user and password, no matter which user i write, it doesn’t connect.
I’ve checked already for the LDAP connection and it’s connected, users appear so o problem connecting to the Domain…
Useful, thanks for sharing.