How to enable Linux firewall(ufw) for custom program running on random port - linux

Question

Written program in python, which chooses random port available for TCP and UDP communication. If I enable Linux firewall(ufw) by running sudo ufw enable. where we can allow any port by giving
sudo ufw allow port_number. As the program can take any random port on run, so can not tell ufw to allow any particular port. Is there any way to tell ufw to allow prog to access any random port by supplying program name to ufw like in windows. In windows firewall, we can supply the following command to allow access to all port for myprog
netsh advfirewall firewall add rule name=rule_name_udp dir=in action=allow protocol=UDP localport=any program=path/myprog.exe
is there any way to allow ufw for my custom program to access for udp/tcp communication with ufw enable?
Thanks to all in advance.

Answer 1

You can wrap your app into systemd service and use post-start hook to call extra bash script which punches holes in firewall.
/path/to/python/app/assistant-ufw-hole-puncher
#!/bin/bash
#extra sleep for prespawn script
sleep 2
#punch holes for TCP ports
ports=`sudo netstat -ntlp 2>&1 |grep yourapp | sed -r 's/(.*:)([0-9]*)(\s.*)/\2/'|sort|uniq`
for port in $ports ; do
sudo ufw allow $port
done
#punch holes for UDP ports
ports=`sudo netstat -nulp 2>&1 |grep yourapp | sed -r 's/(.*:)([0-9]*)(\s.*)/\2/'|sort|uniq`
for port in $ports ; do
sudo ufw allow $port
done
Also you could spawn this script before starting your script but you would need to add extra sleep to wait for python script to start.
#!/bin/bash
/path/to/python/app/assistant-ufw-hole-puncher &
python ./your-app.py