public virtual ActionResult NotFound()
{
LogProvider.WarnFormat("NotFound:{0}", this.Request.RawUrl);
//source: http://www.devcurry.com/2012/06/aspnet-mvc-handling-exceptions-and-404.html
this.Response.StatusCode = 404;
this.Response.TrySkipIisCustomErrors = true;
return this.View();
}