.\" SPDX-License-Identifier: BSD-2-Clause .\" .\" Copyright (c) 2020 Gordon Bergling .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .Dd January 18, 2024 .Dt WG 4 .Os .Sh NAME .Nm wg .Nd WireGuard protocol driver .Sh SYNOPSIS To load the driver as a module at boot time, place the following line in .Xr rc.conf 5 : .Bd -literal -offset indent if_wg_load="YES" .Ed .Pp To compile this driver into the kernel, add the following line to .Xr kernconf 5 kernel configuration file: .Bd -literal -offset indent .Cd pseudo-device wg .Ed .Sh DESCRIPTION The .Nm driver provides Virtual Private Network (VPN) interfaces for the secure exchange of layer 3 traffic with other WireGuard peers using the WireGuard protocol. .Pp A .Nm interface recognizes one or more peers, establishes a secure tunnel with each on demand, and tracks each peer's UDP endpoint for exchanging encrypted traffic with. .Pp The interfaces can be created at runtime using the .Ic ifconfig Cm wg Ns Ar N Cm create command, and then can be configured with .Xr ifconfig 8 . In addition, the .Nm .Xr rc 8 script can be used to easily manage the interfaces; refer to .Xr rc.conf 5 and .Xr wg.conf 5 for the details. .Ss Terminology The following glossary provides a brief overview of WireGuard terminology: .Bl -tag -width indent -offset 3n .It Peer Peers exchange IPv4 or IPv6 traffic over secure tunnels. Each .Nm interface may be configured to recognize one or more peers. .It Key Each peer uses its private key and corresponding public key to identify itself to others. A peer configures a .Nm interface with its own private key and with the public keys of its peers. .It Pre-shared key In addition to the public keys, each peer pair may be configured with a unique pre-shared symmetric key. This is used in their handshake to guard against future compromise of the peers' encrypted tunnel if an attack on their Diffie-Hellman exchange becomes feasible. It is optional, but recommended. .It Allowed IP addresses A single .Nm interface may maintain concurrent tunnels connecting diverse networks. The interface therefore implements rudimentary routing and reverse-path filtering functions for its tunneled traffic. These functions reference a set of allowed IP address ranges configured against each peer. .Pp The interface will route outbound tunneled traffic to the peer configured with the most specific matching allowed IP address range, or drop it if no such match exists. The interface will accept tunneled traffic only from the peer configured with the most specific matching allowed IP address range for the incoming traffic, or drop it if no such match exists. That is, tunneled traffic routed to a given peer cannot return through another peer of the same .Nm interface. This ensures that peers cannot spoof one another's traffic. .It Handshake Two peers handshake to mutually authenticate each other and to establish a shared series of secret ephemeral encryption keys. Either peer may initiate a handshake. Handshakes occur only when there is traffic to send, and recur every two minutes during transfers. .It Connectionless Due to the handshake behavior, there is no connected or disconnected state. .El .Ss Keys Private keys for WireGuard can be generated from any sufficiently secure random source. The Curve25519 keys and the pre-shared keys are both 32 bytes long and are commonly encoded in base64 for ease of use. .Pp Keys can be generated with .Xr openssl 1 as follows: .Pp .Dl $ openssl rand -base64 32 .Pp Although a valid Curve25519 key must have 5 bits set to specific values, this is done by the .Nm interface and so it will accept any random 32-byte base64 string. .Sh EXAMPLES Create a .Nm interface and set random private key: .Bd -literal -offset indent # ifconfig wg0 create # ifconfig wg0 wgkey `openssl rand -base64 32` wgport 54321 .Ed .Pp Retrieve the associated public key from a .Nm interface: .Bd -literal -offset indent $ ifconfig wg0 | grep 'wgpubkey:' .Ed .Pp By default, the private key and pre-shared key (if set) are hidden from the interface status output, but can be made to show up by specifying the .Fl k flag for .Xr ifconfig 8 : .Bd -literal -offset indent # ifconfig -k wg0 | grep -E 'wgkey:|wgpsk:' .Ed .Pp Connect to a specific endpoint using its public-key and set the allowed IP address: .Bd -literal -offset indent # ifconfig wg0 wgpeer \\ wgendpoint 10.0.1.100 54321 \\ wgaip 192.168.2.100/32 .Ed .Pp Set description for a peer: .Bd -literal -offset indent # ifconfig wg0 wgpeer wgdescr .Ed .Pp Remove a peer: .Bd -literal -offset indent # ifconfig wg0 -wgpeer .Ed .Sh DIAGNOSTICS The .Nm interface supports runtime debugging, which can be enabled with: .Pp .D1 Ic ifconfig Cm wg Ns Ar N Cm debug .Pp Some common error messages include: .Bl -tag -width indent .It Sy "Handshake for peer X did not complete after 5 seconds, retrying" Peer X did not reply to our initiation packet, for example because: .Bl -bullet -compact .It The peer does not have the local interface configured as a peer. Peers must be able to mutually authenticate each other. .It The peer's endpoint IP address is incorrectly configured. .It There are firewall rules preventing communication between hosts. .El .It Sy "Invalid handshake initiation" The incoming handshake packet could not be processed. This is likely due to the local interface not containing the correct public key for the peer. .It Sy "Invalid initiation MAC" The incoming handshake initiation packet had an invalid MAC. This is likely because the initiation sender has the wrong public key for the handshake receiver. .It Sy "Packet has disallowed src IP from peer X" After decryption, an incoming data packet has a source IP address that is not assigned to the allowed IPs of Peer X. .El .Sh SEE ALSO .Xr inet 4 , .Xr ip 4 , .Xr netintro 4 , .Xr wg.conf 5 , .Xr ifconfig 8 .Rs .%T WireGuard whitepaper .%U https://www.wireguard.com/papers/wireguard.pdf .Re .Sh HISTORY The .Nm device driver first appeared in .Dx 6.5 , .Fx 13.2 , and .Ox 6.8 . .Sh AUTHORS .An -nosplit The .Nm device driver was written by .An Jason A. Donenfeld Aq Mt Jason@zx2c4.com , .An Matt Dunwoodie Aq Mt ncon@nconroy.net , .An Kyle Evans Aq Mt kevans@FreeBSD.org , and .An Matt Macy Aq Mt mmacy@FreeBSD.org . .Pp This manual page was written by .An Gordon Bergling Aq Mt gbe@FreeBSD.org and is based on the .Ox manual page written by .An David Gwynne Aq Mt dlg@openbsd.org .