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='

Road Warrior Example

With WireGuard, a Road Warrior VPN config is similar to a site-to-site VPN. It just lacks the endpoint address.

In the following example, the IPs for the remote clients are defined in the peers. This would allow the peers to interact with one another.

wireguard wg0 {
    address 10.172.24.1/24
    address 2001:DB8:470:22::1/64
    description RoadWarrior
    peer MacBook {
        allowed-ips 10.172.24.30/32
        allowed-ips 2001:DB8:470:22::30/128
        persistent-keepalive 15
        pubkey F5MbW7ye7DsoxdOaixjdrudshjjxN5UdNV+pGFHqehc=
    }
    peer iPhone {
        allowed-ips 10.172.24.20/32
        allowed-ips 2001:DB8:470:22::30/128
        persistent-keepalive 15
        pubkey BknHcLFo8nOo8Dwq2CjaC/TedchKQ0ebxC7GYn7Al00=
    }
    port 2224
}

The following is the config for the iPhone peer above. It’s important to note that the AllowedIPs setting directs all IPv4 and IPv6 traffic through the connection.

[Interface]
PrivateKey = ARAKLSDJsadlkfjasdfiowqeruriowqeuasdf=
Address = 10.172.24.20/24, 2001:DB8:470:22::20/64
DNS = 10.0.0.53, 10.0.0.54

[Peer]
PublicKey = RIbtUTCfgzNjnLNPQ/ulkGnnB2vMWHm7l2H/xUfbyjc=
AllowedIPs = 0.0.0.0/0, ::/0
Endpoint = 192.0.2.1:2224
PersistentKeepalive = 25

This MacBook peer is doing split-tunneling, where only the subnets local to the server go over the connection.

[Interface]
PrivateKey = 8Iasdfweirousd1EVGUk5XsT+wYFZ9mhPnQhmjzaJE6Go=
Address = 10.172.24.30/24, 2001:DB8:470:22::30/64

[Peer]
PublicKey = RIbtUTCfgzNjnLNPQ/ulkGnnB2vMWHm7l2H/xUfbyjc=
AllowedIPs = 10.172.24.30/24, 2001:DB8:470:22::/64
Endpoint = 192.0.2.1:2224
PersistentKeepalive = 25

Operational commands

Show interface status

[email protected]# run show interfaces wireguard wg01
interface: wg1
    description: VPN-to-wg01
    address: 10.2.0.1/24
    public key: RIbtUTCfgzNjnLNPQ/asldkfjhaERDFl2H/xUfbyjc=
    private key: (hidden)
    listening port: 53665
    peer: to-wg02
        public key: u41jO3OF73Gq1WARMMFG7tOfk7+r8o8AzPxJ1FZRhzk=
        latest handshake: 0:01:20
        status: active
        endpoint: 192.168.0.124:12345
        allowed ips: 10.2.0.0/24
        transfer: 42 GB received, 487 MB sent
        persistent keepalive: every 15 seconds
    RX:
            bytes    packets    errors    dropped    overrun    mcast
    45252407916   31192260         0     244493          0        0
    TX:
        bytes    packets    errors    dropped    carrier    collisions
    511649780    5129601     24465          0          0             0

Show public key of the default key

[email protected]# run show wireguard keypair pubkey default
FAXCPb6EbTlSH5200J5zTopt9AYXneBthAySPBLbZwM=

Show public key of a named key

[email protected]# run show wireguard keypair pubkey KP01
HUtsu198toEnm1poGoRTyqkUKfKUdyh54f45dtcahDM=

Delete wireguard keypairs

[email protected]# wireguard keypair default