Issue Connecting to ROS Network on another computer. "Cannot connect to ROS master"

I have been following tutorials online and those provided by Mathworks such as the one linked here:

https://www.mathworks.com/help/ros/ug/connect-to-a-ros-network.html

I am running MATLAB on a Windows 10 computer while running a ROS master on Ubuntu on a separate one.

I used hostname -I to find the ip address of the computer running the ROS master, and attempted to use rosinit('IPaddress') in MATLAB and other methods such as those mentioned in the tutorial and it fails to connect.

The error is "Cannot connect to ROS master at http://IPaddress:11311. Check the specified address or hostname." Where IPaddress is the address gotten using hostname -I in a linux terminal.

I have no firewall on Ubuntu, and I turned off the firewall on my windows pc to no avail as well.

Both are on the same network/internet (my home internet).

Running roscore, my ROS_MASTER_URI is http://localhost:11311. I am using Ubuntu 16.04 and ROS Kinetic.

Any idea how to fix this issue?

[Cam Salzberger]

Rather than hostname -l, can you try running "ifconfig" on your Ubuntu machine. That should be a more accurate IP address than what is provided by Windows attempting to resolve the hostname.

Also, try pinging both directions (Windows to Ubuntu at that IP, and Ubuntu to Windows at the Windows IP seen by "ipconfig") to make sure communication in general can get through.

[Shivam Bajpai]

Hi,

Did you fix the issue?

Answer 1

[Robert Watson]

I think the problem might be your ROS_MASTER_URI on the computer running roscore. If this is set to local host it can prevent other nodes on the network from accessing it.

To allow external connection, ROS_MASTER_URI set on the host PC should contain its own IP address on the network.

i.e. Both the core host and the client PC should set ROS_MASTER_URI=http://IPaddress:11311