Steve, Much appreciated. I only have FBA enable on the ISA listener. (BTW: I've only one NIC in this box...) A colleague has just suggested something - ISA should definitely work as a proxy for OWA - yes? i.e. it should sit in between the client and the back end server and intercept all communications? Can I confirm that ISA does NOT require to be the gateway (the PIX is the gateway)? As long as I have connectivity, it should proxy incoming connection and subsequent reply? Losing the will.... Regards, Walter