Wireguard on FreeBSD

2023-02-16 - How to configure a wireguard endpoint on FreeBSD
Tags: FreeBSD vpn wireguard

Introduction

This article explains how to configure wireguard on FreeBSD.

Installation

pkg install wireguard

Generating keys

The private and public keys for a host can be generated with the following commands:

PRIVATE_KEY=`wg genkey`
PUBLIC_KEY=`printf $PRIVATE_KEY|wg pubkey`
echo private_key: $PRIVATE_KEY
echo public_key: $PUBLIC_KEY

Configuration

Here is a configuration example of my /usr/local/etc/wireguard/wg0.conf that creates a tunnel listening on udp port 342 and has one remote peer:

[Interface]
PrivateKey = MzrfXLmSfTaCpkJWKwNlCSD20eDq7fo18aJ3Dl1D0gA=
ListenPort = 342
Address = 10.1.2.7/24

[Peer]
PublicKey = R4A01RXXqRJSY9TiKQrZGR85HsFNSXxhRKKEu/bEdTQ=
Endpoint = 168.119.114.183:342
AllowedIPs = 10.1.2.9/32
PersistentKeepalive = 60

To implement this example you will need to generate two sets of keys. The configuration for the first server will feature the first server’s private key in the [Interface] section and the second server’s public key in the [Peer] section, and vice versa for the configuration of the second server.

This example is from a machine that can be hidden behind nat therefore I configure a PersistentKeepalive. If your host has a public IP this line is not needed.

To activate the interface configuration, use :

service wireguard enable
echo 'wireguard_interfaces="wg0"' >> /etc/rc.conf
service wireguard start

Administration

The tunnel can be managed with the wg command:

root@hurricane:~# wg
interface: wg0
  public key: 7fbr/yumFeTzXwxIHnEs462JLFToUyJ7yCOdeDFmP20=
  private key: (hidden)
  listening port: 342

peer: R4A01RXXqRJSY9TiKQrZGR85HsFNSXxhRKKEu/bEdTQ=
  endpoint: 168.119.114.183:342
  allowed ips: 10.1.2.9/32
  latest handshake: 57 seconds ago
  transfer: 1003.48 KiB received, 185.89 KiB sent
  persistent keepalive: every 1 minute

The ip configuration still relies on ifconfig:

root@hurricane:~# ifconfig wg0
wg0: flags=80c1<UP,RUNNING,NOARP,MULTICAST> metric 0 mtu 1420
        options=80000<LINKSTATE>
        inet 10.1.2.7 netmask 0xffffff00
        groups: wg
        nd6 options=109<PERFORMNUD,IFDISABLED,NO_DAD>