## 1. Update your system
First, run the apt command to apply security updates:
```sh
sudo apt update
sudo apt upgrade
```
## 2. Download and run openvpn-install.sh script
DOwnload installation script using short url as follow and update chmod : 
```sh
wget https://git.io/vpn -O openvpn-ubuntu-install.sh
chmod -v +x openvpn-ubuntu-install.sh
sudo ./openvpn-ubuntu-install.sh
```
Select UDP (recomendded), Port default, DNS use 1.1.1.1 or Google, client name, just give some name for example client-vpn, then openvpn will generate file *client-vpn.ovpn* in the /root directory
## 3. Check status, start, stop or restart service
```sh
sudo systemctl status openvpn-server@server.service
sudo systemctl start openvpn-server@server.service
sudo systemctl stop openvpn-server@server.service
sudo systemctl restart openvpn-server@server.service
```

## 4. Using opvn file
On Windows, install OpenVPN GUI and load *client-vpn.ovpn* file. From taskbar, right click OpenVPN icon and select appropriate vpn and click connect. OpenVPN will generate private/local IP addresses such as 10.8.0.1/32

## 5. Test/Verify connection
```sh
ping 10.8.0.1 #Ping to the OpenVPN server gateway
ip route #Make sure routing setup working
## the following must return public IP address of OpenVPN server ##
dig TXT +short o-o.myaddr.l.google.com @ns1.google.com
```

## 6. Add or remove a new VPN user with a certificate
You need to run the same script again for adding or removing a new VPN user to TLS certificate. For instance:
```sh
$ sudo ./openvpn-ubuntu-install.sh
```

This is summary from
[Ubuntu 20.04 LTS Set Up OpenVPN Server In 5 Minutes](https://www.cyberciti.biz/faq/ubuntu-20-04-lts-set-up-openvpn-server-in-5-minutes/)