I want to send the data of posision of the cameras optitrack (windows pc) to ros (ubuntu pc). I was reading many forums and decided to choose the method vrpnclientros. In Motive I have the vrpn broadcast option with ip (239.255.42.99) and a port: 3883. I made a LAN with a router where the windows pc has an ip (192.168.1.18) and the Ubuntu pc has an ip (192.168.1.34). When I run the launch file (roslaunch vrpnclientros sample.launch server: = 239.255.42.99) on a terminal, I get the answers: "Connecting to VRPN server at 239.255.42.99" and "Connection established". My problem is that the topics published do not appear, and therefore I can not get the position data in ros. How can I solve this problem? Do I have to modify the launch file?