How can I open some ports on Ubuntu?

Question

Ubuntu these days comes with UFW – Uncomplicated Firewall. UFW is an easy-to-use method of handling iptables rules.

Try using this command to allow a port:

sudo ufw allow 1701

To test connectivity, you could try shutting down the VPN software (freeing up the ports) and using netcat to listen, like this:

nc -l 1701

Then use telnet from your Windows host and see what shows up on your Ubuntu terminal. This can be repeated for each port you’d like to test.