How to install and configure OpenVPN client on OpenBSD

To install and configure the OpenVPN client on OpenBSD, follow these steps:

1. Install the OpenVPN package using the package manager:

pkg_add openvpn

2. Create a directory to store the OpenVPN configuration files:

mkdir -p /etc/openvpn/client

3. Copy the client configuration file and the necessary certificate and key files to the /etc/openvpn/client directory. The exact configuration and file names will depend on your OpenVPN server setup.

4. Edit the OpenVPN client configuration file and set the following options:

• remote: This option specifies the IP address or hostname of the OpenVPN server.
• ca, cert, and key: These options specify the path to the certificate and key files that the client will use to authenticate to the server.

For example, a basic OpenVPN client configuration file might look like this:

client
dev tun
proto udp
remote my-openvpn-server.com 1194
resolv-retry infinite
nobind
persist-key
persist-tun
ca ca.crt
cert client.crt
key client.key
comp-lzo
verb 3

5. To start the OpenVPN client, run the following command:

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

This will start the OpenVPN client and connect to the specified server.

6. To configure OpenVPN to start automatically at boot time, you will need to create a script to start the client and place it in the /etc/rc.d directory. For example, you could create a script called openvpn-client with the following contents:

#!/bin/sh
#
# $OpenVPN: openvpn-client,v 1.0 2017/07/28 19:01:37 blambert Exp $

if [ -f /etc/openvpn/client/client.conf ] ; then
        echo -n ' openvpn'
        openvpn --daemon --cd /etc/openvpn/client --config client.conf
fi

Make the script executable using the chmod command:

chmod 755 /etc/rc.d/openvpn-client

Then, add the script to the system's startup sequence by running the following command:

rcctl enable openvpn-client