You may need to access to IT resources in your office, home or any other branches. How can you access them unless you have any firewall which supports a vpn connection. The solution is that OpenVpn. Thanks for this link, below, on which I followed the same steps, I set up my vpn connection. I do not want to post all codes in here. I just want to mention rest of it and my implementation.
Step 1. Deploy a lightweight server - Ubuntu or Centos
This is a Ubuntu server for OPENVPN connection. I gave minimum ram, CPU, and disk capacity. I installed an OPENVPN server without graphic user interfaces (GUI) and download my private key, as explained on this link, below. If you have any NAS(Network Area Storage), you can install docker, or a linux server for 7/24 hours connection. There are some examples in the internet.
Step 2. Automatic Startup
Once I turn on my HP server, it is started on VMware ESXI host automatically. I do not need to manage or configure it again. You can access and turn on using ssh and remote IP connection about which I mention on my home lab post.
You can also connect your server and check the status of OPENVPN server side and enable it to start vpn job automatically.
Step 3. Install OPENVPN client application
Client application is an opensource. Click on https://openvpn.net/ website and download one of the version; windows, mac, linux, and upload or drag/drop a private key which was generated on Ubuntu server.
In conclusion, it is useful to use an OPENVPN connection to access home, branch, office networks. Even if you have a public internet connection is more vulnerable such as cafe, airport, you can be in safe by using it.