Hi All,

New to ROS, and trying to get the ROS talker.py node on my laptop to speak to an LXC living on an AWS ec2 instance. I set up iptable rules on the ec2 instance to forward anything coming in on port 25002 to the same port on the lxc. However, I cannot get the talker node connected to the listener (which is run on the LXC).

As an experiment I set up a pipe, called back on the ec2 instance, and am having it pipe everything coming through on por 25002 to the same port on the lxc:

cat back | nc -l 25002 | nc 10.0.3.20 25003 > back

where 10.0.3.20 is the local IP of the lxc, and on that instance I run:

nc -l 25003

Netcat then echoes back to the terminal:

POST /RPC2 HTTP/1.1
Host: xx.xxx.xx.xxx:25002
Accept-Encoding: gzip
User-Agent: xmlrpclib.py/1.0.1 (by www.pythonware.com)
Content-Type: text/xml
Content-Length: 389

<?xml version='1.0'?>
<methodCall>
<methodName>registerPublisher</methodName>
<params>
<param>
<value><string>/talker_30504_1420566191918</string></value>
</param>
<param>
<value><string>/chatter</string></value>
</param>
<param>
<value><string>std_msgs/String</string></value>
</param>
<param>
<value><string>http://xxx-MacBookPro:41567/</string></value>
</param>
</params>
</methodCall>

However, if I try to run the launchfile with listener.py on port 52002 and switch up the above command to:

cat back | nc -l 25002 | nc 10.0.3.20 25002 > back

Then when I try to run talker I get

[ERROR] [WallTime: 1420565703.326813] Unable to immediately register with master node [http://xx.xxx.xx.xxx:25002]: master may not be running yet. Will keep trying.

While running roswtf on the listener side yields:

ERROR Could not contact the following nodes:

 * /talker_30365_1420565451591
 * /talker_30378_1420565461600
 * /talker_30390_1420565508134
 * /talker_30435_1420565680145
 * /talker_30530_1420566770564
 * /talker_30313_1420564757936

ERROR The following nodes should be connected but aren't:
 * /talker_30365_1420565451591->/rosout (/rosout)
 * /talker_30378_1420565461600->/rosout (/rosout)

I thought the talker should open a port back on the local machine on the same port? How can I go about allowing my local machine to accept connections back from the master? Thanks.

while true; do cat back | nc -l 25002 | nc 10.0.3.20 25002 > back; done;