Necessary Priviledges for AD authentication

I'm linking my authentication to Active Directory using the article http://msdn.microsoft.com/en-us/library/ms998360.aspx .  I need users in the OU 'Students' to be able to authenticate, and right now the account that I'm using in the web.config membership provider only has generic rights over that OU.  The account does have full admin rights over another OU and users who belong to that OU are able to authenticate.  My question is what kind of privileges will  i need to request from IT services to allow users in the Students OU to authenticate?
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