windows authentication

i having problems accessing the clients domain\username information.  in the IIS, the "integrated windows authentication" is the only ticked box.  my web config is setup as follows
<authentication mode="Windows"></authentication>
<authorization>
      <deny users="?"/>
  </authorization>
is there anything else i should be doing ?  all i get is the local administrator account ....  I hope its not something basic....
but any help is appreciated
thanks
 
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