WG(4) Device Drivers Manual WG(4)

wgvirtual private network tunnel (EXPERIMENTAL)

pseudo-device wg

The wg interface implements a roaming-capable virtual private network tunnel, configured with ifconfig(8) and wgconfig(8).

wg is experimental.

Packets exchanged on a wg interface are authenticated and encrypted with a secret key negotiated with the peer, and the encapsulation is exchanged over IP or IPv6 using UDP.

Every wg interface can be configured with an IP address using ifconfig(8), a private key generated with wg-keygen(8), an optional listen port, and a collection of peers.

Each peer configured on an wg interface has a public key and a range of IP addresses the peer is allowed to use for its wg interface inside the tunnel. Each peer may also optionally have a preshared secret key and a fixed endpoint IP address outside the tunnel.

Typical network topology:

Stationary server:                         Roaming client:
+---------+                                    +---------+
|    A    |                                    |    B    |
|---------|                                    |---------|
|         | 192.0.2.123          198.51.100.45 |         |
|        [wm0]----------internet-----------[bge0]        |
|    [wg0] port 1234 - - - (tunnel) - - - - - - [wg0]    |
|   10.2.0.1                  |               10.2.0.42  |
|   fd00:2::1                 |              fd00:2::42  |
|         |                   |                |         |
+--[wm1]--+          +-----------------+       +---------+
     | 10.1.0.1      | VPN 10.2.0.0/24 |
     |               |     fd00:2::/64 |
     |               +-----------------+
+-----------------+
| LAN 10.1.0.0/24 |
|     fd00:1::/64 |
+-----------------+

Generate key pairs on A and B:

A# (umask 0077; wg-keygen > /etc/wg/wg0)
A# wg-keygen --pub < /etc/wg/wg0 > /etc/wg/wg0.pub
A# cat /etc/wg/wg0.pub
N+B4Nelg+4ysvbLW3qenxIwrJVE9MdjMyqrIisH7V0Y=

B# (umask 0077; wg-keygen > /etc/wg/wg0)
B# wg-keygen --pub < /etc/wg/wg0 > /etc/wg/wg0.pub
B# cat /etc/wg/wg0.pub
X7EGm3T3IfodBcyilkaC89j0SH3XD6+/pwvp7Dgp5SU=

Generate a pre-shared key on A and copy it to B to defend against potential future quantum cryptanalysis (not necessary for functionality):

A# (umask 0077; wg-keygen > /etc/wg/wg0.A-B)

Configure A to listen on port 1234 and allow connections from B to appear in the 10.2.0.0/24 and fd00:2::/64 subnets:

A# ifconfig wg0 create
A# ifconfig wg0 inet 10.2.0.1/24
A# ifconfig wg0 inet6 fd00:2::1/64
A# wgconfig wg0 set private-key /etc/wg/wg0
A# wgconfig wg0 set listen-port 1234
A# wgconfig wg0 add peer B \
    X7EGm3T3IfodBcyilkaC89j0SH3XD6+/pwvp7Dgp5SU= \
    --preshared-key=/etc/wg/wg0.A-B \
    --allowed-ips=10.2.0.42/32,fd00:2::42/128
A# ifconfig wg0 up
A# ifconfig wg0
wg0: flags=0x8041<UP,RUNNING,MULTICAST> mtu 1420
        status: active
        inet6 fe80::22f7:d6ff:fe3a:1e60%wg0/64 flags 0 scopeid 0x3
        inet6 fd00:2::1/64 flags 0
        inet 10.2.0.1/24 flags 0

You can put all these commands in /etc/ifconfig.wg0 so that the interface gets configured automatically during startup:

A# cat /etc/ifconfig.wg0
net 10.2.0.1/24
inet6 fd00:2::1/64
!wgconfig $int set private-key /etc/wg/wg0
!wgconfig $int set listen-port 1234
!wgconfig $int add peer B X7EGm3T3IfodBcyilkaC89j0SH3XD6+/pwvp7Dgp5SU= \
    --preshared-key=/etc/wg/wg0.A-B \
    --allowed-ips=10.2.0.42/32,fd00:2::1/128
up

Configure B to connect to A at 192.0.2.123 on port 1234 and the packets can begin to flow:

B# ifconfig wg0 create
B# ifconfig wg0 inet 10.2.0.42/24
B# ifconfig wg0 inet6 fd00:2::42/64
B# wgconfig wg0 set private-key /etc/wg/wg0
B# wgconfig wg0 add peer A \
    N+B4Nelg+4ysvbLW3qenxIwrJVE9MdjMyqrIisH7V0Y= \
    --preshared-key=/etc/wg/wg0.A-B \
    --allowed-ips=10.2.0.1/32,fd00:2::1/128 \
    --endpoint=192.0.2.123:1234
B# ifconfig wg0 up
B# ifconfig wg0
wg0: flags=0x8041<UP,RUNNING,MULTICAST> mtu 1420
        status: active
        inet6 fe80::56eb:59ff:fe3d:d413%wg0/64 flags 0 scopeid 0x3
        inet6 fd00:2::42/64 flags 0
        inet 10.2.0.42/24 flags 0
B# ping -n 10.2.0.1
PING 10.2.0.1 (10.2.0.1): 56 data bytes
64 bytes from 10.2.0.1: icmp_seq=0 ttl=255 time=2.721110 ms
...
B# ping6 -n fd00:2::1
PING6(56=40+8+8 bytes) fd00:2::42 --> fd00:2::1
16 bytes from fd00:2::1, icmp_seq=0 hlim=64 time=2.634 ms
...

Same as before, you can put all these commands in /etc/ifconfig.wg0 so that the interface gets configured automatically during startup:

B# cat /etc/ifconfig.wg0
inet 10.2.0.42/24
inet6 fd00:2::42/64
!wgconfig $int set private-key /etc/wg/wg0
!wgconfig $int add peer A N+B4Nelg+4ysvbLW3qenxIwrJVE9MdjMyqrIisH7V0Y= \
    --preshared-key=/etc/wg/wg0.A-B \
    --allowed-ips=10.2.0.1/32,fd00:2::1/128 \
    --endpoint=192.0.2.123:1234
up

wg-keygen(8), wgconfig(8), wg-userspace(8)

The wg interface aims to be compatible with the WireGuard protocol, as described in:

Jason A. Donenfeld, WireGuard: Next Generation Kernel Network Tunnel, https://web.archive.org/web/20180805103233/https://www.wireguard.com/papers/wireguard.pdf, 2018-06-30, Document ID: 4846ada1492f5d92198df154f48c3d54205657bc.

The wg interface first appeared in NetBSD 10.0.

The wg interface was implemented by Ryota Ozaki <ozaki.ryota@gmail.com>.

December 16, 2024 NetBSD 10.99