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Ros running on 2 machines, one master, subscriber not getting any message

asked 2017-02-20 07:54:35 -0600

highWaters gravatar image


I have the following configuration with two machines running on Ubuntu: On one machine I run the ros master, and a listener (tutorial one)

On the other I have a talker (again from the tutorial). I set the ROS_MASTER_URI as specified in . I am able to ping between the machines, and use netcat to send msgs back and forth from the command lines. I have allowed port 11311 with ufw.

If I run the talker, the listener doesn't get any message. If I run rqt_graph it shows the nodes and the topic on which they publish/subscribe. The listener node's color is in red, and nothing changes if I hover on it.

Any idea for what could be the issue?

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It's likely that you don't have your ROS environment variables setup correctly. Please edit your question to describe the exact values for ROS_MASTER_URI, ROS_HOSTNAME, and ROS_IP on both machines.

jarvisschultz gravatar image jarvisschultz  ( 2017-02-20 10:03:22 -0600 )edit

If you are using HOSTNAME, you need to have consistent /etc/hosts files on both machines

dcconner gravatar image dcconner  ( 2017-02-20 10:04:32 -0600 )edit

2 Answers

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answered 2017-02-20 10:15:18 -0600

highWaters gravatar image

Disabling ufw completely solved the problem. The weird thing is that, this was working once without the need to disable ufw.

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You can simply allow traffic in your LAN, no need to deactivate ufw completely.

$ sudo ufw allow from

arminf82 gravatar image arminf82  ( 2019-09-07 05:15:27 -0600 )edit

answered 2017-02-21 11:44:15 -0600

duck-development gravatar image

You have to open all ports on the subscriber not only the ros core port. Run the both nodes and see the ports with

 netstat -tulpen
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Asked: 2017-02-20 07:54:35 -0600

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Last updated: Feb 21 '17