I have tried the gamut of combinations but cannot seem to find the key.  I am attempting to use a DNN 3.3.5 portal with mixed mode authentication.  The theory is: Clients on the network will not have to log into child portals.  Clients off network will use username and password as registered to log into child portals over SSL.  Root portal is not used.  Documentation seems to indicate:

1. authentication mode in web.config should be "Forms"
2. httpmodule "authentication" in web.config should be uncommented
3. windowssignin.aspx in auth dir should not allow anonymous access via iis
4. windows authentication settings in child portal should be set as "delegation" authentication type, root domain to tree of users LDAP://OU=users,OU=philadelphia,DC=ad,DC=ringTonep,DC=com, and username and password are not necessary as all network users have read access to AD.

The above settings do not allow network users to open child portals without manual login using AD credentials.  This existing portal has over 100 child portals and thousands of existing users.

Thank you for any assistance

The instructions in the link you supply suggest removing from trusted and adding to intranet zone on the local client.  Conversly, your note suggest adding domain to trusted zone of the local client.  I have now tried both without success.  To add to the confusion, the link you supplied has conflicting information to this post http://www.dotnetnuke.com/DotNetNukeProjects/CoreActiveDirectory/tabid/840/EntryID/234/Default.aspx  on the project page as it indicates you do not need a single username and password since all network users have read access to ad.  The following four points seem to be key in getting autologin to function and yet autologin does not function on child portals.

1. authentication mode in web.config should be "Forms"
2. httpmodule "authentication" in web.config should be uncommented
3. windowssignin.aspx in auth dir should not allow anonymous access via iis
4. windows authentication settings in child portal should be set as "delegation" authentication type, root domain to tree of users LDAP://OU=users,OU=philadelphia,DC=ad,DC=ringTonep,DC=com, and username and password are not necessary as all network users have read access to AD.