Hi Ken, It reports: None I am confused here. I thought I could either use the IP address or the name to locate the machine. I prefer IP address. I am pretty sure that the two IPs of my two machines are correct. Can I use the IP to set ROS_IP and ROS_MASTER_URI ?? Thanks. Chris -- View this message in context: http://ros-users.122217.n3.nabble.com/roslaunch-for-multiple-machines-tp1918649p1919434.html Sent from the ROS-Users mailing list archive at Nabble.com.