Hi Jacob: The secondary mx and any others for that matter are to do exactly what you suspected. You set the priority at say zero for your primary and maybe 5 or ten for your secondary and then if your primary machine isn't up, it gets the host on the other end to move onto the next machine. in thhe priority ranking. Kirk -- Kirk Reiser The Computer Braille Facility e-mail: kirk at braille.uwo.ca University of Western Ontario phone: (519) 661-3061