openvpn server config

openvpn.md

Find your IP address

Find local IP

ip addr

Find external IP

dig +short myip.opendns.com @resolver1.opendns.com

Command dig can be installed as below

On Debian/Ubuntu:

sudo apt install dnsutils

On Arch/Manjaro:

sudo pacman -Sy bind

Download and run installation script

Download script

wget https://git.io/vpn -O openvpn-ubuntu-install.sh

Make script executable

chmod -v +x openvpn-ubuntu-install.sh

Run the script

sudo ./openvpn-ubuntu-install.sh

It will then generate a .ovpn file under /root/

Config the server

Start service

sudo systemctl start openvpn

Config the router

Open UDP port 1194 in firewall

Config the clicent

Copy .ovpn file from server to client

scp your_username@your_external_ip:/root/your_ovpn_filename.ovpn .

If root is not allowed to login into the server, use following command

ssh your_username@your_external_ip "sudo -S cat /root/your_ovpn_filename.ovpn" > your_ovpn_filename.ovpn

On Windows

Use OpenVPN GUI

On Linux

From terminal

Copy .ovpn file as follows

sudo cp your_ovpn_filename.ovpn /etc/openvpn/client.conf

Connect from CLI

sudo openvpn --client --config /etc/openvpn/client.conf

From NetworkManager

Go to Settings -> Network -> VPN -> Add VPN -> Import from file... and select the .ovpn file

Verify/Test

ping 10.8.0.1
ip route
dig +short myip.opendns.com @resolver1.opendns.com

Check OpenVPN serverfor errors

sudo journalctl --identifier ovpn-server

Check firewall rules

cat /etc/systemd/system/openvpn-iptables.service

Another option is to run iptables command and sysctl command commands to verify NAT rule setup on your server

sudo iptables -t nat -L -n -v
sysctl net.ipv4.ip_forward

Insert the rules if not inserted using the following command

sudo systemctl start openvpn-iptables.service
sudo sysctl -w net.ipv4.ip_forward=1

Check open port

sudo netstat -tulpn | grep :1194