This kind of question is best asked on answers.ros.org.

Consider this answer:
http://answers.ros.org/question/90536/ros-remote-master-can-see-topics-but-no-data/


On 21.10.2013 16:39, Sudarshan Srinivasan wrote:
> Hey,
>
> I followed the actionlib tutorial given here 
> <http://wiki.ros.org/actionlib_tutorials/Tutorials/Writing%20a%20Simple%20Action%20Server%20using%20the%20Execute%20Callback%20%28Python%29> and 
> created fibonacci_server.py and fibonacci_client.py which I have 
> attached. If I run roscore on the same computer as I'm running the 
> server and client, the whole connection (server-client) works and I am 
> able to echo the feedback, status, result etc. However, when I run 
> roscore on a remote machine i.e. a remote ROS master by setting my 
> ROS_MASTER_URI, the process does not work. I even made sure that they 
> have the same time by running ntpdate on both machines.
>
> Both computers are running Ubuntu 12.04 with ROS Groovy. Is there 
> something more I need to do in order to make the action server work 
> with a remote ROS master? Please let me know if you need more 
> information and thanks for your help.
>
> Sudarshan.
>
>
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