Preface and Context: I am currently troubleshooting the ROS2/LAN based connection of my UR5 CB3 robotic arm with the Ubunut 22 control comupter and the respective driver. This robotic arm seems to require communication via port 50002, but for some reason my computer refuses the connection. If you are curious about the details, I described it in detail here: https://forum.universal-robots.com/t/controlling-a-ur5-cb3-with-ros2-and-ubunut-22-connection-refused/33432
Current problem: In order to further understand where the problem is, I connected my control-computer to an unrelated Laptop, that also runs Ubuntu 22. I used static IPv4 adresses and predefined ports (12345 and 4444), since my original problem requires me to use this way of communication. I wanted to understand if I can connect the two computer and transfer a file. I used netcat and this tutorial but I could not transfer a file via the connection. Using the wifi Router with automatic settings works though. I turned off the firewall using:
$ sudo ufw disable
The pinging of the IPs (192.168.1.101 and 192.168.1.103) using
jann@xps13:~$ ping 192.168.1.101
yields:
PING 192.168.1.101 (192.168.1.101) 56(84) bytes of data. 64 bytes from 192.168.1.101: icmp_seq=1 ttl=64 time=3.03 ms 64 bytes from 192.168.1.101: icmp_seq=2 ttl=64 time=1.75 ms 64 bytes from 192.168.1.101: icmp_seq=3 ttl=64 time=1.60 ms
This makes me think that the physical connection works, but there must be some kind of software problem related to the static IPv4 that I don't understand. I did my best to look for possible solutions online, but I am not exactly a network guy, I might have missed something.
When I scan the network from my laptop with netcat I get the following result:
jann@xps13:~$ netcat -z -n -v 192.168.1.101 50001-50009
netcat: connect to 192.168.1.101 port 50001 (tcp) failed: Connection timed out netcat: connect to 192.168.1.101 port 50002 (tcp) failed: Connection refused netcat: connect to 192.168.1.101 port 50003 (tcp) failed: Connection timed out netcat: connect to 192.168.1.101 port 50004 (tcp) failed: Connection timed out netcat: connect to 192.168.1.101 port 50005 (tcp) failed: Connection timed out netcat: connect to 192.168.1.101 port 50006 (tcp) failed: Connection timed out
Do you guys have any idea how I could approach the next steps of troubleshooting?
