Change openVPN port number:
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*You may want to change the openVPN port number to reduce bad actors knowing what port your system is on, as well as trying to get around firewalls for public WiFi networks that are set to block openVPN default port number (UDP 1194). Its best to change to a common port that you wont use. In this case we will change to POP2's port number (since its for email but is very dated now).

To change openVPN port number:
edit the server config file with this command:
sudo nano /etc/openvpn/server/server.conf

Change the default port from (UDP 1194) to TCP 109 (This is for POP2, a very dated email port that is no longer often used by clients).

When done, save the file and restart your server, running "sudo systemctl restart openvpn" does NOT work for some reason.

In case you want to see if your openvpn server is working after reboot, run "sudo systemctl status openvpn"

Last thing is for each client .opvn file, you need to change there port numbers to be correct as well as re-import then to the openVPN client apps for android and ios since they cant be edited through the app.

Also add the new port number (in this case TCP 109) to your routers firewall since you wont be able to connect remotely if not done this way.


You should be now fully set!

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Sources:
https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers
https://openvpn.net/community-resources/how-to/#determining-whether-to-use-a-routed-or-bridged-vpn


Date: February 23rd 2024.