Deploy an OpenVPN service on a Raspberry Pi or VPS

This article will guide you through the installation and configuration of an OpenVPN service on a Raspberry Pi with Raspberry Pi OS. This guide is valid as well for other Debian-based distributions, like Ubuntu Server.

Getting the installation script

curl -L https://install.pivpn.io -o /tmp/install.sh

This will download the pivpn installation script into a the /tmp folder. At this point you can peek into the script to inspect its content.

The next step is to execute the installation script.

Installation and Configuration

Run the script with the bash interpreter.

bash /tmp/install.sh

After checking for requirements, you should be greeted with:

Local IP of the server

The first important configuration step is to make sure that the device that will act as the OpenVPN server, the Pi in this case, has a static LAN IP. This can be done on your router, or on the device itself. In the former case, the DHCP service of your router will make sure to assign the same local IP address to your device, identified among others by the MAC address of its network interface. In the latter case, the static IP is configured in the /etc/network/interfaces file. The device would then send the requested static IP to the router, when the corresponding network interface is started.

If you have already setup a DHCP reservation on your router, for that particular device, choose "Yes". Otherwise, this is your chance to setup a static LAN IP address. Also, make sure that the Gateway address corresponds to the IP of your router.

The step that follows is trivial and requires you to choose a user, who will hold the configuration profile. After that, choose "OpenVPN" and go with the proposed settings on the step that follows.

OpenVPN port

At this point you have the opportunity to choose the port on which the OpenVPN server will be listening to, 1194 being the default port number. Pick a value and write it down, since it will have to be allowed by your firewall, and by your router, since the OpenVPN clients will connect to it from outside of your network.

DNS server

Pick the DNS server of your choice. You have the possibility to set a custom one, e.g. pointing to your router in case it is running a DNS service.

External IP or Dynamic DNS

Unless your internet provider is providing you with a static external IP that does not change, you need to enter here your dynamic DNS name, i.e. the server name that resolves to your external IP, and updates it when the latter is changed by your internet provider (typically when the router is restarted). The IP address or name that you set up will end up in the client configuration profiles, generated at the end of this guide, and will serve as the target endpoint to which clients will connect to. Setting up a dynamic DNS is left out of scope of this guide.

Enable unattended upgrades

Since the server will be listening for connections from outside of your network, it is recommended to enable unattended upgrades of security patches. This feature will make your server check for available upgrades automatically and regularly, and apply them when necessary.

Opening up the way for connections (firewall + router)

If you are using ufw as your firewall, the script should automatically detect it and add an "allow rule" on "1194/udp", assuming you have choosen that port, and kept UDP as the transport protocol. Check that the rule is indeed present:

sudo ufw status

You can also restrict further the rule, for example if you know from which IP addresses will connect the OpenVPN clients.

You should be left with the configuration of "port forwarding" on your router. Details are left outside of this guide, since router interfaces vary, but it usually boils down to instructing the following to your router, again assuming that you are using 1194 as OpenVPN port value and UDP as transport protocol:

UDP connections to port 1194 should be forwarded to <local IP of your server, port 1194>

Configure a client

While the service has now been configured, we now need to generate client profiles for client devices which will communicate with the VPN server. For example, a profile for your laptop. Create a new profile with:

pivpn ovpn add

This will generate a .ovpn file, and will save it in the directory $HOME/ovpns. That is the file you'll need to transfer to the client.

Final step

The final step is to get an OpenVPN client for your client device, and import the profile previously created.