OpenVPN Setup (Server & Client)

Environment

VPN Server

Field Spec or Version
CPU QEMU Virtual CPU version 2.5+ (2 Cores)
RAM 2G
OS Ubuntu 24.04.1 LTS (Noble Numbat)
Network interface ens18 with static IP 192.168.3.100/24
DNS 192.168.3.1 (Private DNS Server)

VPN Client

Field Spec or Version
CPU QEMU Virtual CPU version 2.5+ (2 Cores)
RAM 2G
OS Ubuntu 24.04.1 LTS (Noble Numbat)
Network interface ens18 with static IP 192.168.5.100/24
DNS 192.168.5.1 (Private DNS Server)

Field	Spec or Version
CPU	QEMU Virtual CPU version 2.5+ (2 Cores)
RAM	2G
OS	Ubuntu 24.04.1 LTS (Noble Numbat)
Network	interface ens18 with static IP 192.168.3.100/24
DNS	192.168.3.1 (Private DNS Server)

Field	Spec or Version
CPU	QEMU Virtual CPU version 2.5+ (2 Cores)
RAM	2G
OS	Ubuntu 24.04.1 LTS (Noble Numbat)
Network	interface ens18 with static IP 192.168.5.100/24
DNS	192.168.5.1 (Private DNS Server)

Server - Package Installation

apt install -y openvpn

Server - Configuration

Copy from sample configuration file

cp /usr/share/doc/openvpn/examples/sample/config-files/server.conf /etc/openvpn/server/server.conf

Edit the copied file

port 1194
proto tcp

# Use routing mode instead of bridge mode
dev tun

ca ca.crt
cert example.fake.crt
key example.fake.key
dh dh.pem

topology subnet
server 192.168.7.0 255.255.255.0

# Add route for subnet on server to connected VPN clients
push "route 192.168.3.0 255.255.255.0"