The NBOSVM is not able to communicate with the nbosdmapi on the controller node

If the NBOS VM port is blocked on the controller node, NBOS VM is not able to communicate with the nbosdmapi on the controller node.

If the NBOS VM is configured with HTTPS, the port is 13784. If NBOSVM is configured with HTTP, the port is 8784.

To enable the port on all the controller nodes

Run the following command to identify the DROP iptables rule line number:
iptables -L --line-numbers | grep -i DROP
Run the following command to insert the iptables rule before the DROP rule.
sudo iptables -I INPUT <linenumber> -p tcp -s <nbosvm subnet> --dport <HTTP/HTTPS port number> -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT
For example, if the DROP iptables rule line number is 88, the NBOSVM subnet is 10.xxx.xxx.xx/20, and NBOSVM is configured with HTTPS, the command is:
sudo iptables -I INPUT 87 -p tcp -s 10.xxx.xxx.xx/20 --dport 13784 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT