HttpContext.Current.User.Identity.IsAuthenticated

Hi
We have an SharePoint site no login (anonymous) with a search module using AJAX. Now the users complains that the module isn't working. When I check the code (not developed by me), I find that the code only runs if "HttpContext.Current.User.Identity.IsAuthenticated=true". Could that ever return true on an anonymous site?
Best Regards,
Niclas
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