WireGuard VPN Interface

WireGuard is an extremely simple yet fast and modern VPN that utilizes state-of-the-art cryptography. See https://www.wireguard.com for more information.

Configuration

Wireguard requires the generation of a keypair, a private key which will decrypt incoming traffic and a public key, which the peer(s) will use to encrypt traffic.

Generate a keypair

Generate the keypair, which creates a public and private part and stores it within VyOS. It will be used per default on any configured wireguard interface, even if multiple interfaces are being configured.

wg01:~$ configure
wg01# run generate wireguard keypair

The public key is being shared with your peer(s), your peer will encrypt all traffic to your system using this public key.

wg01# run show wireguard pubkey
u41jO3OF73Gq1WARMMFG7tOfk7+r8o8AzPxJ1FZRhzk=

Generate named keypairs

Named keypairs can be used on a interface basis, if configured. If multiple wireguard interfaces are being configured, each can have their own keypairs.

The commands below will generate 2 keypairs, which are not related to each other.

wg01:~$ configure
wg01# run generate wireguard named-keypairs KP01
wg01# run generate wireguard named-keypairs KP02

Wireguard Interface configuration

The next step is to configure your local side as well as the policy based trusted destination addresses. If you only initiate a connection, the listen port and endpoint is optional, if you however act as a server and endpoints initiate the connections to your system, you need to define a port your clients can connect to, otherwise it’s randomly chosen and may make it difficult with firewall rules, since the port may be a different one when you reboot your system.

You will also need the public key of your peer as well as the network(s) you want to tunnel (allowed-ips) to configure a wireguard tunnel. The public key below is always the public key from your peer, not your local one.

local side

set interfaces wireguard wg01 address '10.1.0.1/24'
set interfaces wireguard wg01 description 'VPN-to-wg02'
set interfaces wireguard wg01 peer to-wg02 allowed-ips '10.2.0.0/24'
set interfaces wireguard wg01 peer to-wg02 endpoint '192.168.0.142:12345'
set interfaces wireguard wg01 peer to-wg02 pubkey 'XMrlPykaxhdAAiSjhtPlvi30NVkvLQliQuKP7AI7CyI='
set interfaces wireguard wg01 port '12345'
set protocols static interface-route 10.2.0.0/24 next-hop-interface wg01

Note

The endpoint must be an IP and not a fully qualified domain name (FQDN). Using a FQDN will result in unexpected behavior.

The last step is to define an interface route for 10.2.0.0/24 to get through the wireguard interface wg01. Multiple IPs or networks can be defined and routed, the last check is allowed-ips which either prevents or allows the traffic.

To use a named key on an interface, the option private-key needs to be set.

set interfaces wireguard wg01 private-key KP01
set interfaces wireguard wg02 private-key KP02

The command run show wireguard named-keypairs pubkey KP01 will then show the public key, which needs to be shared with the peer.

remote side

set interfaces wireguard wg01 address '10.2.0.1/24'
set interfaces wireguard wg01 description 'VPN-to-wg01'
set interfaces wireguard wg01 peer to-wg02 allowed-ips '10.1.0.0/24'
set interfaces wireguard wg01 peer to-wg02 endpoint '192.168.0.124:12345'
set interfaces wireguard wg01 peer to-wg02 pubkey 'u41jO3OF73Gq1WARMMFG7tOfk7+r8o8AzPxJ1FZRhzk='
set interfaces wireguard wg01 port '12345'
set protocols static interface-route 10.1.0.0/24 next-hop-interface wg01

Assure that your firewall rules allow the traffic, in which case you have a working VPN using wireguard.

wg01# ping 10.2.0.1
PING 10.2.0.1 (10.2.0.1) 56(84) bytes of data.
64 bytes from 10.2.0.1: icmp_seq=1 ttl=64 time=1.16 ms
64 bytes from 10.2.0.1: icmp_seq=2 ttl=64 time=1.77 ms

wg02# ping 10.1.0.1
PING 10.1.0.1 (10.1.0.1) 56(84) bytes of data.
64 bytes from 10.1.0.1: icmp_seq=1 ttl=64 time=4.40 ms
64 bytes from 10.1.0.1: icmp_seq=2 ttl=64 time=1.02 ms

An additional layer of symmetric-key crypto can be used on top of the asymmetric crypto, which is optional.

wg01# run generate wireguard preshared-key
rvVDOoc2IYEnV+k5p7TNAmHBMEGTHbPU8Qqg8c/sUqc=

Copy the key, as it is not stored on the local file system. Make sure you distribute that key in a safe manner, it’s a symmetric key, so only you and your peer should have knowledge of its content.

wg01# set interfaces wireguard wg01 peer to-wg02 preshared-key 'rvVDOoc2IYEnV+k5p7TNAmHBMEGTHbPU8Qqg8c/sUqc='
wg02# set interfaces wireguard wg01 peer to-wg01 preshared-key 'rvVDOoc2IYEnV+k5p7TNAmHBMEGTHbPU8Qqg8c/sUqc='

Operational commands

Show interface status

vyos@wg01# run show interfaces wireguard wg01

interface: wg01
public key: xHvgSJC8RTClfvjc0oX6OALxU6GGLapjthjw7x82CSw=
private key: (hidden)
listening port: 12345

peer: 9Ek3R30mG6Vk+GHsENtPF0b9Ul+ftxx4dDBa1bdBxX8=
endpoint: 192.168.0.142:12345
allowed ips: 10.2.0.0/24
latest handshake: 4 minutes, 22 seconds ago
transfer: 860 B received, 948 B sent

Show public key of the default key

vyos@wg01# run show wireguard keypair pubkey default
FAXCPb6EbTlSH5200J5zTopt9AYXneBthAySPBLbZwM=

Show public key of a named key

vyos@wg01# run show wireguard keypair pubkey KP01
HUtsu198toEnm1poGoRTyqkUKfKUdyh54f45dtcahDM=

Delete wireguard keypairs

vyos@wg01# wireguard keypair default