Ready to configure DotNetNuke to use Active Directory for authentication? Here are some basic instructions for configuring AD in DNN that works with DNN 4.5.3:
ADMIN SETTINGS
1. Log into DNN as Host
2. Go to Admin > Authentication
3. Check "Windows Authentication".
4. Check "Synchronize Role?"
5. Provider is "ADSIAuthenticationProvider"
6. AuthType is "Delegation"
7. Domain: dc=yourdomainminusthedotcom, dc=com
8. Email domain: @yourdomain.com
9. Click "Update".
10. You should see a message like this...unless it does not work 
:
Accessing Global Catalog:
OK
Checking Root Domain:
OK
Accessing LDAP:
OK
Find all domains in network:
1 Domain(s):
yourdomain.com (SN)
IIS SETTINGS:
1. Open IIS Manager and find the following file within the DNN site: /Admin/Security/WindowsSignin.aspx,
2. Right click on WindowsSigin.aspx and select “Properties”
3. Click “File Security” tab
4. Click “Edit” in the ‘Authentication and access control’ section
5. UNCheck box for "Enable anonymous access" and check "Integrated Windows authentication".
6. Choose “OK” until out of the Properties box
ENABLE AUTHENTICATION HTTPMODULE IN WEB.CONFIG:
1. Open web.config file with editor
2. UNComment the authentication in httpmodule section (<httpmodules>) in Web.config and save file:
<add name="Authentication" type="DotNetNuke.HttpModules.AuthenticationModule, DotNetNuke.HttpModules.Authentication" />
You should be able to login and authenticate to the site.
We performed an upgrade and Active Directory configuration this morning for a client, using DNN 4.5.3 and the above instructions worked flawlessly. This is a slightly modified version of instructions found on the DNN Forums by kimberlyrox.