Hey Greg, Are you able to ping the other machines from your master computer? Also, is there a way that you can disable any possible firewall that may exist by having that router?
Try running this <a href="http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=B45EACE3EEDF56A4E034080020E74861&p_node=174821 ">Remote VI Status Monitor example</a>. Final idea for now, anyway of trying out different port numbers for the client computers on the other side of the firewall?
