WireGuard - ArchWiki (2024)

From the WireGuard project homepage:

WireGuard is an extremely simple yet fast and modern VPN that utilizes state-of-the-art cryptography. It aims to be faster, simpler, leaner, and more useful than IPsec, while avoiding the massive headache. It intends to be considerably more performant than OpenVPN. WireGuard is designed as a general purpose VPN for running on embedded interfaces and super computers alike, fit for many different circ*mstances. Initially released for the Linux kernel, it is now cross-platform (Windows, macOS, BSD, iOS, Android) and widely deployable.

A rough introduction to the main concepts used in this article can be found on WireGuard's project homepage. WireGuard has been included in the Linux kernel since late 2019.

Installation

Install the wireguard-tools package for userspace utilities.

Alternatively, various network managers provide support for WireGuard, provided that peer keys are available. See #Persistent configuration for details.

Graphical clients

• wireguird — A linux GTK GUI client for WireGuard.

https://github.com/UnnoTed/wireguird || wireguird^AUR

Command-line tools

• wg_tool — Tool to manage wireguard configs for server and users.

https://github.com/gene-git/wg_tool || wg_tool^AUR

• wg-client — Linux client with both command line and GUI.

https://github.com/gene-git/wg-client || wg-client^AUR

• wg2nd — A tool to convert WireGuard configurations from wg-quick(8) format into systemd-networkd compatible configurations.

https://git.flu0r1ne.net/wg2nd/about || wg2nd^AUR

Usage

The commands below demonstrate how to set up a basic tunnel between two or more peers with the following settings:

Tip: The same UDP port can be used for all peers.

The external addresses should already exist. For example, if ICMP echo requests are not blocked, peer A should be able to ping peer B via its public IP address(es) and vice versa.

The internal addresses will be new addresses, created either manually using the ip(8) utility or by network management software, which will be used internally within the new WireGuard network. The following examples will use 10.0.0.0/24 and fdc9:281f:04d7:9ee9::/64 as the internal network. The /24 and /64 in the IP addresses is the CIDR.

Key generation

Create a private and public key for each peer. If connecting dozens of peers optionally consider a vanity keypair to personalize the Base64 encoded public key string. See #Vanity keys.

To create a private key run:

$ (umask 0077; wg genkey > peer_A.key)

Note: It is recommended to only allow reading and writing access for the owner. The above alters the umask temporarily within a sub-shell to ensure that access (read/write permissions) is restricted to the owner.

To create a public key:

$ wg pubkey < peer_A.key > peer_A.pub

Alternatively, do this all at once:

$ wg genkey | (umask 0077 && tee peer_A.key) | wg pubkey > peer_A.pub

One can also generate a pre-shared key to add an additional layer of symmetric-key cryptography to be mixed into the already existing public-key cryptography, for post-quantum resistance. A pre-shared key should be generated for each peer pair and should not be reused. For example, three interconnected peers, A, B, and, C will need three separate pre-shared keys, one for each peer pair.

Generate a pre-shared key for each peer pair using the following command (make sure to use umask 0077 for this as well):

$ wg genpsk > peer_A-peer_B.psk$ wg genpsk > peer_A-peer_C.psk$ wg genpsk > peer_B-peer_C.psk

Vanity keys

Currently, WireGuard does not support comments or attaching human-memorable names to keys. This makes identifying the key's owner difficult particularly when multiple keys are in use. One solution is to generate a public key that contains some familiar characters (perhaps the first few letters of the owner's name or of the hostname etc.), wireguard-vanity-address does this.

For example:

$ wireguard-vanity-address --in 8 leslie

searching for 'leslie' in pubkey[0..10], one of every 214748364 keys should matchone core runs at 2.69e6 keys/s, CPU cores available: 16est yield: 5.0 seconds per key, 200.10e-3 keys/sh*t Ctrl-C to stopprivate wEoVMj92P+E3fQXVf9IixWJqpCqcnP/4OfvrB1g3zmY= public LEsliEny+aMcWcRbh8Qf414XsQHSBOAFk3TaEk/aSD0=private EAOwlGGqpHVbZ9ehaCspdBJt+lkMcCfkwiA5T5a4JFs= public VlesLiEB5BFd//OD2ILKXviolfz+hodG6uZ+XjoalC8=private UDWG4VWI+RzAGzNSnlC+0X4d3nk9goWPs/NRC5tX524= public 9lESlieIFOlJFV6dG7Omao2WS+amWgshDdBYn8ahRjo=

Manual configuration

Peer setup

Manual setup is accomplished by using ip(8) and wg(8).

Note: These examples use the pre-shared keys which were introduced as optional in #Key generation. If not using them, simply ignore the corresponding parts in the commands.

Peer A setup:

In this example, peer A will listen on UDP port 51871 and will accept connection from peers B and C.

# ip link add dev wg0 type wireguard# ip addr add 10.0.0.1/24 dev wg0# ip addr add fdc9:281f:04d7:9ee9::1/64 dev wg0# wg set wg0 listen-port 51871 private-key /path/to/peer_A.key# wg set wg0 peer PEER_B_PUBLIC_KEY preshared-key /path/to/peer_A-peer_B.psk endpoint peer-b.example:51902 allowed-ips 10.0.0.2/32,fdc9:281f:04d7:9ee9::2/128# wg set wg0 peer PEER_C_PUBLIC_KEY preshared-key /path/to/peer_A-peer_C.psk allowed-ips 10.0.0.3/32,fdc9:281f:04d7:9ee9::3/128# ip link set wg0 up

PEER_X_PUBLIC_KEY should be the contents of peer_X.pub.

The keyword allowed-ips is a list of addresses that will get routed to the peer. Make sure to specify at least one address range that contains the WireGuard connection's internal IP address(es).

Peer B setup:

# ip link add dev wg0 type wireguard# ip addr add 10.0.0.2/24 dev wg0# ip addr add fdc9:281f:04d7:9ee9::2/64 dev wg0# wg set wg0 listen-port 51902 private-key /path/to/peer_B.key# wg set wg0 peer PEER_A_PUBLIC_KEY preshared-key /path/to/peer_A-peer_B.psk endpoint 198.51.100.101:51871 allowed-ips 10.0.0.1/32,fdc9:281f:04d7:9ee9::1/128# wg set wg0 peer PEER_C_PUBLIC_KEY preshared-key /path/to/peer_B-peer_C.psk allowed-ips 10.0.0.3/32,fdc9:281f:04d7:9ee9::3/128# ip link set wg0 up

Peer C setup:

# ip link add dev wg0 type wireguard# ip addr add 10.0.0.3/24 dev wg0# ip addr add fdc9:281f:04d7:9ee9::3/64 dev wg0# wg set wg0 listen-port 51993 private-key /path/to/peer_C.key# wg set wg0 peer PEER_A_PUBLIC_KEY preshared-key /path/to/peer_A-peer_C.psk endpoint 198.51.100.101:51871 allowed-ips 10.0.0.1/32,fdc9:281f:04d7:9ee9::1/128# wg set wg0 peer PEER_B_PUBLIC_KEY preshared-key /path/to/peer_B-peer_C.psk endpoint peer-b.example:51902 allowed-ips 10.0.0.2/32,fdc9:281f:04d7:9ee9::2/128# ip link set wg0 up

Additional routes

To establish connections more complicated than point-to-point, additional setup is necessary.

Point-to-site

To access the network of a peer, specify the network subnet(s) in allowed-ips in the configuration of the peers who should be able to connect to it. E.g. allowed-ips 10.0.0.2/32,fdc9:281f:04d7:9ee9::2/128,192.168.35.0/24,fd7b:d0bd:7a6e::/64.

Make sure to also set up the routing table with ip-route(8). E.g.:

# ip route add 192.168.35.0/24 dev wg0# ip route add fd7b:d0bd:7a6e::/64 dev wg0

Site-to-point

If the intent is to connect a device to a network with WireGuard peer(s), set up routes on each device so they know that the peer(s) are reachable via the device.

Tip: Deploy routes network-wide by configuring them in the router.

After that, enable IP forwarding on the peer through which other devices on the network will connect to WireGuard peer(s).

Site-to-site

To connect two (or more) networks, apply both #Point-to-site and #Site-to-point on all sites.

Routing all traffic over WireGuard

To route all traffic through a peer, set the AllowedIPs to all known IP addresses, i.e. "AllowedIPs = 0.0.0.0/0,::0"

In a simple wg-quick conf it would be something like this:

Peer B setup:

/etc/wireguard/wg0.conf

[Interface]Address = 10.0.0.2/24, fdc9:281f:04d7:9ee9::2/64PrivateKey = DEADBEEFDNS = 10.0.0.12[Peer]PublicKey = PEER_C_PUBLIC_KEYAllowedIPs = 0.0.0.0/0,::/0Endpoint = 10.1.2.3:52180

Further explanation and some python to work out how to exclude ranges can found here.[2]

DNS

To use a peer as a DNS server, add its WireGuard tunnel IP address(es) to /etc/resolv.conf. For example, to use peer B as the DNS server:

/etc/resolv.conf

nameserver fdc9:281f:04d7:9ee9::2nameserver 10.0.0.2

Note: If a peer will act as a DNS server, make sure to use its WireGuard tunnel address(es) as the DNS server address(es) instead of another of its addresses from allowed IPs. Otherwise DNS lookups may fail.

Basic checkups

Invoking the wg(8) command without parameters will give a quick overview of the current configuration.

As an example, when peer A has been configured we are able to see its identity and its associated peers:

# wg

interface: wg0 public key: UguPyBThx/+xMXeTbRYkKlP0Wh/QZT3vTLPOVaaXTD8= private key: (hidden) listening port: 51871peer: 9jalV3EEBnVXahro0pRMQ+cHlmjE33Slo9tddzCVtCw= endpoint: 203.0.113.102:51902 allowed ips: 10.0.0.2/32, fdc9:281f:04d7:9ee9::2peer: 2RzKFbGMx5g7fG0BrWCI7JIpGvcwGkqUaCoENYueJw4= endpoint: 192.0.2.103:51993 allowed ips: 10.0.0.3/32, fdc9:281f:04d7:9ee9::3

At this point one could reach the end of the tunnel. If the peers do not block ICMP echo requests, try pinging a peer to test the connection between them.

Using ICMPv4:

$ ping 10.0.0.2

Using ICMPv6:

$ ping fdc9:281f:04d7:9ee9::2

After transferring some data between peers, the wg utility will show additional information:

# wg

interface: wg0 public key: UguPyBThx/+xMXeTbRYkKlP0Wh/QZT3vTLPOVaaXTD8= private key: (hidden) listening port: 51871peer: 9jalV3EEBnVXahro0pRMQ+cHlmjE33Slo9tddzCVtCw= endpoint: 203.0.113.102:51902 allowed ips: 10.0.0.2/32, fdc9:281f:04d7:9ee9::2 latest handshake: 5 seconds ago transfer: 1.24 KiB received, 1.38 KiB sentpeer: 2RzKFbGMx5g7fG0BrWCI7JIpGvcwGkqUaCoENYueJw4= allowed ips: 10.0.0.3/32, fdc9:281f:04d7:9ee9::3

Persistent configuration

Persistent configuration can be achieved using [email protected], which is shipped with wireguard-tools, or using a network manager. Network managers that support WireGuard are systemd-networkd, netctl[3], NetworkManager and ConnMan[4].

wg-quick

wg-quick(8) configures WireGuard tunnels using configuration files from /etc/wireguard/interfacename.conf.

The current WireGuard configuration can be saved by utilizing the wg(8) utility's showconf command. For example:

# wg showconf wg0 > /etc/wireguard/wg0.conf

To start a tunnel with a configuration file, use

# wg-quick up interfacename

or use the systemd service—wg-quick@interfacename.service. To start the tunnel at boot, enable the unit.

Peer A setup:

/etc/wireguard/wg0.conf

[Interface]Address = 10.0.0.1/24, fdc9:281f:04d7:9ee9::1/64ListenPort = 51871PrivateKey = PEER_A_PRIVATE_KEY[Peer]PublicKey = PEER_B_PUBLIC_KEYPresharedKey = PEER_A-PEER_B-PRESHARED_KEYAllowedIPs = 10.0.0.2/32, fdc9:281f:04d7:9ee9::2/128Endpoint = peer-b.example:51902[Peer]PublicKey = PEER_C_PUBLIC_KEYPresharedKey = PEER_A-PEER_C-PRESHARED_KEYAllowedIPs = 10.0.0.3/32, fdc9:281f:04d7:9ee9::3/128

• To route all traffic through the tunnel to a specific peer, add the default route (0.0.0.0/0 for IPv4 and ::/0 for IPv6) to AllowedIPs. E.g. AllowedIPs = 0.0.0.0/0,::/0. wg-quick will automatically take care of setting up correct routing and fwmark[6] so that networking still functions.
• To use a peer as a DNS server, set DNS = wireguard_internal_ip_address_of_peer in the [Interface] section. Search domains are also set with the DNS = option. Separate all values in the list with commas.

Peer B setup:

/etc/wireguard/wg0.conf

[Interface]Address = 10.0.0.2/24, fdc9:281f:04d7:9ee9::2/64ListenPort = 51902PrivateKey = PEER_B_PRIVATE_KEY[Peer]PublicKey = PEER_A_PUBLIC_KEYPresharedKey = PEER_A-PEER_B-PRESHARED_KEYAllowedIPs = 10.0.0.1/32, fdc9:281f:04d7:9ee9::1/128Endpoint = 198.51.100.101:51871[Peer]PublicKey = PEER_C_PUBLIC_KEYPresharedKey = PEER_B-PEER_C-PRESHARED_KEYAllowedIPs = 10.0.0.3/32, fdc9:281f:04d7:9ee9::3/128

Peer C setup:

/etc/wireguard/wg0.conf

[Interface]Address = 10.0.0.3/24, fdc9:281f:04d7:9ee9::3/64ListenPort = 51993PrivateKey = PEER_C_PRIVATE_KEY[Peer]PublicKey = PEER_A_PUBLIC_KEYPresharedKey = PEER_A-PEER_C-PRESHARED_KEYAllowedIPs = 10.0.0.1/32, fdc9:281f:04d7:9ee9::1/128Endpoint = 198.51.100.101:51871[Peer]PublicKey = PEER_B_PUBLIC_KEYPresharedKey = PEER_B-PEER_C-PRESHARED_KEYAllowedIPs = 10.0.0.2/32, fdc9:281f:04d7:9ee9::2/128Endpoint = peer-b.example:51902

systemd-networkd

systemd-networkd has native support for setting up WireGuard interfaces. An example is provided in the systemd.netdev(5) § EXAMPLES man page.

Note: Routing all DNS over WireGuard (i.e. Domains=~.) will prevent the DNS resolution of endpoints. Unless the peer domain is configured to be resolved on a specific network link.

Peer A setup:

/etc/systemd/network/99-wg0.netdev

[NetDev]Name=wg0Kind=wireguardDescription=WireGuard tunnel wg0[WireGuard]ListenPort=51871PrivateKey=PEER_A_PRIVATE_KEY[WireGuardPeer]PublicKey=PEER_B_PUBLIC_KEYPresharedKey=PEER_A-PEER_B-PRESHARED_KEYAllowedIPs=10.0.0.2/32AllowedIPs=fdc9:281f:04d7:9ee9::2/128Endpoint=peer-b.example:51902[WireGuardPeer]PublicKey=PEER_C_PUBLIC_KEYPresharedKey=PEER_A-PEER_C-PRESHARED_KEYAllowedIPs=10.0.0.3/32AllowedIPs=fdc9:281f:04d7:9ee9::3/128

/etc/systemd/network/99-wg0.network

[Match]Name=wg0[Network]Address=10.0.0.1/24Address=fdc9:281f:04d7:9ee9::1/64

• To use a peer as a DNS server, specify its WireGuard tunnel's IP address(es) in the .network file using the DNS= option. For search domains use the Domains= option. See systemd.network(5) § [NETWORK] SECTION OPTIONS for details.
• To use a peer as the only DNS server, then in the .network file's [Network] section set DNSDefaultRoute=true and add ~. to Domains= option.
• To route additional subnets add them as [Route] sections in the .network file. For example:

/etc/systemd/network/99-wg0.network

...[Route]Destination=192.168.35.0/24Scope=link[Route]Destination=fd7b:d0bd:7a6e::/64Scope=link

# chown root:systemd-network /etc/systemd/network/99-*.netdev# chmod 0640 /etc/systemd/network/99-*.netdev

Peer B setup:

/etc/systemd/network/99-wg0.netdev

[NetDev]Name=wg0Kind=wireguardDescription=WireGuard tunnel wg0[WireGuard]ListenPort=51902PrivateKey=PEER_B_PRIVATE_KEY[WireGuardPeer]PublicKey=PEER_A_PUBLIC_KEYPresharedKey=PEER_A-PEER_B-PRESHARED_KEYAllowedIPs=10.0.0.1/32AllowedIPs=fdc9:281f:04d7:9ee9::1/128Endpoint=198.51.100.101:51871[WireGuardPeer]PublicKey=PEER_C_PUBLIC_KEYPresharedKey=PEER_B-PEER_C-PRESHARED_KEYAllowedIPs=10.0.0.3/32AllowedIPs=fdc9:281f:04d7:9ee9::3/128

/etc/systemd/network/99-wg0.network

[Match]Name=wg0[Network]Address=10.0.0.2/24Address=fdc9:281f:04d7:9ee9::2/64

Peer C setup:

/etc/systemd/network/99-wg0.netdev

[NetDev]Name=wg0Kind=wireguardDescription=WireGuard tunnel wg0[WireGuard]ListenPort=51993PrivateKey=PEER_C_PRIVATE_KEY[WireGuardPeer]PublicKey=PEER_A_PUBLIC_KEYPresharedKey=PEER_A-PEER_C-PRESHARED_KEYAllowedIPs=10.0.0.1/32AllowedIPs=fdc9:281f:04d7:9ee9::1/128Endpoint=198.51.100.101:51871[WireGuardPeer]PublicKey=PEER_B_PUBLIC_KEYPresharedKey=PEER_B-PEER_C-PRESHARED_KEYAllowedIPs=10.0.0.2/32AllowedIPs=fdc9:281f:04d7:9ee9::2/128Endpoint=peer-b.example:51902

/etc/systemd/network/99-wg0.network

[Match]Name=wg0[Network]Address=10.0.0.3/24Address=fdc9:281f:04d7:9ee9::3/64

systemd-networkd: routing all traffic over WireGuard

In this example, Peer B connects to Peer A with a public IP address. Peer B routes all its traffic over the WireGuard tunnel and uses Peer A for handling DNS requests.

Peer A setup

/etc/systemd/network/99-wg0.netdev

[NetDev]Name=wg0Kind=wireguardDescription=WireGuard tunnel wg0[WireGuard]ListenPort=51871PrivateKey=PEER_A_PRIVATE_KEY[WireGuardPeer]PublicKey=PEER_B_PUBLIC_KEYPresharedKey=PEER_A-PEER_B-PRESHARED_KEYAllowedIPs=10.0.0.2/32

/etc/systemd/network/99-wg0.network

[Match]Name=wg0[Network]Address=10.0.0.1/24

$ ufw route allow in on wg0 out on enp5s0

/etc/ufw/before.rules

*nat:POSTROUTING ACCEPT [0:0]-A POSTROUTING -s 10.0.0.0/24 -o enp5s0 -j MASQUERADECOMMIT

Peer B setup:

/etc/systemd/network/99-wg0.netdev

[NetDev]Name=wg0Kind=wireguardDescription=WireGuard tunnel wg0[WireGuard]ListenPort=51902PrivateKey=PEER_B_PRIVATE_KEYFirewallMark=0x8888[WireGuardPeer]PublicKey=PEER_A_PUBLIC_KEYPresharedKey=PEER_A-PEER_B-PRESHARED_KEYAllowedIPs=0.0.0.0/0Endpoint=198.51.100.101:51871

/etc/systemd/network/50-wg0.network

[Match]Name=wg0[Network]Address=10.0.0.2/24DNS=10.0.0.1DNSDefaultRoute=trueDomains=~.[RoutingPolicyRule]FirewallMark=0x8888InvertRule=trueTable=1000Priority=10# Exempt the endpoint IP address so that wireguard can still connect to it.[RoutingPolicyRule]To=198.51.100.101/32Priority=5[Route]Destination=0.0.0.0/0Table=1000

Exempting specific addresses

In order to exempt specific addresses (such as private LAN addresses) from routing over the WireGuard tunnel, add them to a higher-priority RoutingPolicyRule than the one that was just created. This will configure them to use the default routing table, and prevent them from using the WireGuard table.

/etc/systemd/network/50-wg0.network

...[RoutingPolicyRule]To=192.168.0.0/24Priority=9...

Route for specific user

It may be desirable to route WAN traffic over the tunnel only for a specific user, for example, the transmission user in order to use the tunnel for torrent traffic.

/etc/systemd/network/99-wg0.network

...[RoutingPolicyRule]Table=8677User=transmissionPriority=30001Family=both[RoutingPolicyRule]Table=mainUser=transmissionSuppressPrefixLength=0Priority=30000Family=both...

/etc/systemd/network/99-wg0.netdev

...[WireGuard]PrivateKey='PEER_PRIVATE_KEY'RouteTable=8677...

Netctl

Netctl has native support for setting up WireGuard interfaces. A typical set of WireGuard netctl profile configuration files would look like this:

Peer A setup:

/etc/netctl/wg0

Description="WireGuard tunnel on peer A"Interface=wg0Connection=wireguardWGConfigFile=/etc/wireguard/wg0.confIP=staticAddress=('10.0.0.1/24')

/etc/wireguard/wg0.conf

[Interface]ListenPort = 51871PrivateKey = PEER_A_PRIVATE_KEY[Peer]PublicKey = PEER_B_PUBLIC_KEYAllowedIPs = 10.0.0.2/32Endpoint = peer-b.example:51902[Peer]PublicKey = PEER_C_PUBLIC_KEYAllowedIPs = 10.0.0.3/32

Peer B setup:

/etc/netctl/wg0

Description="WireGuard tunnel on peer B"Interface=wg0Connection=wireguardWGConfigFile=/etc/wireguard/wg0.confIP=staticAddress=('10.0.0.2/24')

/etc/wireguard/wg0.conf

[Interface]ListenPort = 51902PrivateKey = PEER_B_PRIVATE_KEY[Peer]PublicKey = PEER_A_PUBLIC_KEYAllowedIPs = 10.0.0.1/32Endpoint = peer-a.example:51871[Peer]PublicKey = PEER_C_PUBLIC_KEYAllowedIPs = 10.0.0.3/32

Peer C setup:

/etc/netctl/wg0

Description="WireGuard tunnel on peer C"Interface=wg0Connection=wireguardWGConfigFile=/etc/wireguard/wg0.confIP=staticAddress=('10.0.0.3/24')

/etc/wireguard/wg0.conf

[Interface]ListenPort = 51993PrivateKey = PEER_C_PRIVATE_KEY[Peer]PublicKey = PEER_A_PUBLIC_KEYAllowedIPs = 10.0.0.1/32Endpoint = peer-a.example:51871[Peer]PublicKey = PEER_B_PUBLIC_KEYAllowedIPs = 10.0.0.2/32Endpoint = peer-b.example:51902

Then start and/or enable the wg0 interface on every participating peer as needed, i.e.

# netctl start wg0

To implement persistent site-to-peer, peer-to-site or site-to-site type of connection with WireGuard and Netctl, just add appropriate Routes= line into the netctl profile configuration file and add this network to AllowedIPs in the WireGuard profile, e.g. Routes=('192.168.10.0/24 dev wg0') in the /etc/netctl/wg0 and AllowedIPs=10.0.0.1/32, 192.168.10.0/24 in /etc/wireguard/wg0.conf and then do not forget to enable IP forwarding.

NetworkManager

NetworkManager has native support for setting up WireGuard interfaces. For all details about WireGuard usage in NetworkManager, read Thomas Haller's blog post—WireGuard in NetworkManager.

# nmcli connection import type wireguard file /etc/wireguard/wg0.conf

Note: nmcli can create a WireGuard connection profile, but it does not support configuring peers. See NetworkManager issue 358.

The following examples configure WireGuard via the keyfile format .nmconnection files. See nm-settings-keyfile(5) and nm-settings(5) for an explanation on the syntax and available options.

Peer A setup:

/etc/NetworkManager/system-connections/wg0.nmconnection

[connection]id=wg0type=wireguardinterface-name=wg0[wireguard]listen-port=51871private-key=PEER_A_PRIVATE_KEYprivate-key-flags=0[wireguard-peer.PEER_B_PUBLIC_KEY]endpoint=peer-b.example:51902preshared-key=PEER_A-PEER_B-PRESHARED_KEYpreshared-key-flags=0allowed-ips=10.0.0.2/32;fdc9:281f:04d7:9ee9::2/128;[wireguard-peer.PEER_C_PUBLIC_KEY]preshared-key=PEER_A-PEER_C-PRESHARED_KEYpreshared-key-flags=0allowed-ips=10.0.0.3/32;fdc9:281f:04d7:9ee9::3/128;[ipv4]address1=10.0.0.1/24method=manual[ipv6]address1=fdc9:281f:04d7:9ee9::1/64method=manual

• To route all traffic through the tunnel to a specific peer, add the default route (0.0.0.0/0 for IPv4 and ::/0 for IPv6) to wireguard-peer.PEER_X_PUBLIC_KEY.allowed-ips. E.g. wireguard-peer.PEER_B_PUBLIC_KEY.allowed-ips=0.0.0.0/0;::/0;. Special handling of the default route in WireGuard connections is supported since NetworkManager 1.20.0.
• To use a peer as a DNS server, specify its WireGuard tunnel's IP address(es) with the ipv4.dns and ipv6.dns settings. Search domains can be specified with the ipv4.dns-search= and ipv6.dns-search= options. See nm-settings(5) for more details. For example, using the keyfile format:

...[ipv4]...dns=10.0.0.2;dns-search=corp;...[ipv6]...dns=fdc9:281f:04d7:9ee9::2;dns-search=corp;...

To use a peer as the only DNS server, set a negative DNS priority (e.g. dns-priority=-1) and add ~. to the dns-search= settings.

Peer B setup:

/etc/NetworkManager/system-connections/wg0.nmconnection

[connection]id=wg0type=wireguardinterface-name=wg0[wireguard]listen-port=51902private-key=PEER_B_PRIVATE_KEYprivate-key-flags=0[wireguard-peer.PEER_A_PUBLIC_KEY]endpoint=198.51.100.101:51871preshared-key=PEER_A-PEER_B-PRESHARED_KEYpreshared-key-flags=0allowed-ips=10.0.0.1/32;fdc9:281f:04d7:9ee9::1/128;[wireguard-peer.PEER_C_PUBLIC_KEY]preshared-key=PEER_B-PEER_C-PRESHARED_KEYpreshared-key-flags=0allowed-ips=10.0.0.3/32;fdc9:281f:04d7:9ee9::3/128;[ipv4]address1=10.0.0.2/24method=manual[ipv6]address1=fdc9:281f:04d7:9ee9::2/64method=manual

Peer C setup:

/etc/NetworkManager/system-connections/wg0.nmconnection

[connection]id=wg0type=wireguardinterface-name=wg0[wireguard]listen-port=51993private-key=PEER_C_PRIVATE_KEYprivate-key-flags=0[wireguard-peer.PEER_A_PUBLIC_KEY]endpoint=198.51.100.101:51871preshared-key=PEER_A-PEER_C-PRESHARED_KEYpreshared-key-flags=0allowed-ips=10.0.0.1/32;fdc9:281f:04d7:9ee9::1/128;[wireguard-peer.PEER_B_PUBLIC_KEY]endpoint=peer-b.example:51902preshared-key=PEER_B-PEER_C-PRESHARED_KEYpreshared-key-flags=0allowed-ips=10.0.0.2/32;fdc9:281f:04d7:9ee9::2/128;[ipv4]address1=10.0.0.3/24method=manual[ipv6]address1=fdc9:281f:04d7:9ee9::3/64method=manual

Specific use-case: VPN server

Note: Usage of the terms "server" and "client" were purposefully chosen in this section specifically to help new users/existing OpenVPN users become familiar with the construction of WireGuard's configuration files. WireGuard documentation simply refers to both of these concepts as "peers."

The purpose of this section is to set up a WireGuard "server" and generic "clients" to enable access to the server/network resources through an encrypted and secured tunnel like OpenVPN and others. The "server" runs on Linux and the "clients" can run on any number of platforms (the WireGuard Project offers apps on both iOS and Android platforms in addition to Linux, Windows and MacOS). See the official project install link for more.

Tip: Instead of using wireguard-tools for server/client configuration, one may also use systemd-networkd native WireGuard support.

Server

On the peer that will act as the "server", first enable IPv4 forwarding.

If the server has a public IP configured, be sure to:

• Allow UDP traffic on the specified port(s) on which WireGuard will be running (for example allowing traffic on 51820/UDP).
• Setup the forwarding policy for the firewall if it is not included in the WireGuard configuration for the interface itself /etc/wireguard/wg0.conf. The example below should have the iptables rules and work as-is.

If the server is behind NAT, be sure to forward the specified port(s) on which WireGuard will be running (for example, 51820/UDP) from the router to the WireGuard server.

Key generation

Generate key pairs for the server and for each client as explained in #Key generation.

Server configuration

Create the "server" configuration file:

/etc/wireguard/wg0.conf

[Interface]Address = 10.200.200.1/24ListenPort = 51820PrivateKey = SERVER_PRIVATE_KEY# substitute eth0 in the following lines to match the Internet-facing interface# the FORWARD rules will always be needed since traffic needs to be forwarded between the WireGuard# interface and the other interfaces on the server.# if the server is behind a router and receives traffic via NAT, specify static routing back to the# 10.200.200.0/24 subnet, the NAT iptables rules are not needed but the FORWARD rules are needed.# if the server is behind a router and receives traffic via NAT but one cannot specify static routing back to# 10.200.200.0/24 subnet, both the NAT and FORWARD iptables rules are needed. PostUp = iptables -A FORWARD -i %i -j ACCEPT; iptables -A FORWARD -o %i -j ACCEPT; iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADEPostDown = iptables -D FORWARD -i %i -j ACCEPT; iptables -D FORWARD -o %i -j ACCEPT; iptables -t nat -D POSTROUTING -o eth0 -j MASQUERADE[Peer]# fooPublicKey = PEER_FOO_PUBLIC_KEYPresharedKey = PRE-SHARED_KEYAllowedIPs = 10.200.200.2/32[Peer]# barPublicKey = PEER_BAR_PUBLIC_KEYPresharedKey = PRE-SHARED_KEYAllowedIPs = 10.200.200.3/32

Additional peers ("clients") can be listed in the same format as needed. Each peer requires the PublicKey to be set. However, specifying PresharedKey is optional.

Notice that the Address has a netmask of /24 and the clients on AllowedIPs /32. The clients only use their IP and the server only sends back their respective addresses.

The interface can be managed manually using wg-quick(8) or using a systemd service managed via systemctl(1).

The interface may be brought up using wg-quick up wg0 respectively by starting and potentially enabling the interface via wg-quick@interface.service, e.g. [email protected]. To close the interface use wg-quick down wg0 respectively stop wg-quick@interface.service.

Client configuration

Create the corresponding "client" configuration file(s):

foo.conf

[Interface]Address = 10.200.200.2/32PrivateKey = PEER_FOO_PRIVATE_KEYDNS = 10.200.200.1[Peer]PublicKey = SERVER_PUBLICKEYPresharedKey = PRE-SHARED_KEYEndpoint = my.ddns.example.com:51820AllowedIPs = 0.0.0.0/0,::/0

bar.conf

[Interface]Address = 10.200.200.3/32PrivateKey = PEER_BAR_PRIVATE_KEYDNS = 10.200.200.1[Peer]PublicKey = SERVER_PUBLICKEYPresharedKey = PRE-SHARED KEYEndpoint = my.ddns.example.com:51820AllowedIPs = 0.0.0.0/0,::/0

Using the catch-all AllowedIPs = 0.0.0.0/0,::/0 will forward all IPv4 (0.0.0.0/0) and IPv6 (::/0) traffic over the VPN.

Note: Users of NetworkManager, may need to enable the NetworkManager-wait-online.service and users of systemd-networkd may need to enable the systemd-networkd-wait-online.service to wait until devices are network-ready before attempting a WireGuard connection.

Testing the tunnel

Once a tunnel has been established, one can use netcat to send traffic through it to test out throughput, CPU usage, etc.On one side of the tunnel, run nc in listen mode and on the other side, pipe some data from /dev/zero into nc in sending mode.

In the example below, port 2222 is used for the traffic (be sure to allow traffic on port 2222 if using a firewall).

On one side of the tunnel listen for traffic:

$ nc -vvlnp 2222

On the other side of the tunnel, send some traffic:

$ dd if=/dev/zero bs=1024K count=1024 | nc -v 10.0.0.203 2222

Status can be monitored using wg directly.

# wg

interface: wg0 public key: UguPyBThx/+xMXeTbRYkKlP0Wh/QZT3vTLPOVaaXTD8= private key: (hidden) listening port: 51820peer: 9jalV3EEBnVXahro0pRMQ+cHlmjE33Slo9tddzCVtCw= preshared key: (hidden) endpoint: 192.168.1.216:53207 allowed ips: 10.0.0.0/0 latest handshake: 1 minutes, 17 seconds ago transfer: 56.43 GiB received, 1.06 TiB sent

Tips and tricks

Store private keys in encrypted form (wg-quick)

It may be desirable to store private keys in encrypted form, such as through use of pass. Just replace the PrivateKey line under [Interface] in the WireGuard configuration file with:

PostUp = wg set %i private-key <(su user -c "export PASSWORD_STORE_DIR=/path/to/your/store/; pass WireGuard/private-keys/%i")

where user is the Linux username of interest. See the wg-quick(8) man page for more details.

Alternatively, systemd-creds can be used. This can be helpful to create encrypted private keys that are bound to the system's TPM. See systemd-creds(1) for more details.

First, create an encrypted credential:

# echo -n your_wg_private_key | systemd-creds --tpm2-device=auto encrypt - /etc/credstore.encrypted/wg-private-key.cred

Finally, replace the PrivateKey line under [Interface] in the WireGuard configuration file with:

PostUp = wg set %i private-key <(systemd-creds decrypt /etc/credstore.encrypted/wg-private-key.cred)

Store private keys in TPM (systemd-networkd)

Check whether your system supports TPM2:

# systemd-creds has-tpm2

Store your keys:

# echo -n your_wg_private_key | systemd-creds encrypt - /etc/credstore.encrypted/network.wireguard.private.wg0# echo -n your_pre_shared_key | systemd-creds encrypt - /etc/credstore.encrypted/network.wireguard.psk.wg0

(Note that the name of the store must match network.wireguard.*.)

Modify your .netdev file to use

PrivateKey = @network.wireguard.private.wg0PresharedKey = @network.wireguard.psk.wg0

Endpoint with changing IP

After resolving a server's domain, WireGuard will not check for changes in DNS again.

If the WireGuard server is frequently changing its IP-address due DHCP, Dyndns, IPv6, etc., any WireGuard client is going to lose its connection, until its endpoint is updated via something like wg set "$INTERFACE" peer "$PUBLIC_KEY" endpoint "$ENDPOINT".

Also be aware, if the endpoint is ever going to change its address (for example when moving to a new provider/datacenter), just updating DNS will not be enough, so periodically running reresolve-dns might make sense on any DNS-based setup.

Luckily, wireguard-tools provides an example script /usr/share/wireguard-tools/examples/reresolve-dns/reresolve-dns.sh, that parses WG configuration files and automatically resets the endpoint address.

One needs to run the /usr/share/wireguard-tools/examples/reresolve-dns/reresolve-dns.sh /etc/wireguard/wg.conf periodically to recover from an endpoint that has changed its IP.

One way of doing so is by updating all WireGuard endpoints once every thirty seconds[7] via a systemd timer:

/etc/systemd/system/wireguard_reresolve-dns.timer

[Unit]Description=Periodically reresolve DNS of all WireGuard endpoints[Timer]OnCalendar=*:*:0/30[Install]WantedBy=timers.target

/etc/systemd/system/wireguard_reresolve-dns.service

[Unit]Description=Reresolve DNS of all WireGuard endpointsWants=network-online.targetAfter=network-online.target[Service]Type=oneshotExecStart=/bin/sh -c 'for i in /etc/wireguard/*.conf; do /usr/share/wireguard-tools/examples/reresolve-dns/reresolve-dns.sh "$i"; done'

Afterwards enable and start wireguard_reresolve-dns.timer

Generate QR code

If the client is a mobile device such as a phone, qrencode can be used to generate client's configuration QR code and display it in terminal:

$ qrencode -t ansiutf8 -r client.conf

Enable debug logs

When using the Linux kernel module on a kernel that supports dynamic debugging, debugging information can be written into the kernel ring buffer (viewable with dmesg and journalctl) by running:

# modprobe wireguard# echo module wireguard +p > /sys/kernel/debug/dynamic_debug/control

Reload peer (server) configuration

In case the WireGuard peer (mostly server) adding or removing another peers from its configuration and wants to reload it without stopping any active sessions, one can execute the following command to do it:

# wg syncconf ${WGNET} <(wg-quick strip ${WGNET})

Where $WGNET is WireGuard interface name or configuration base name, for example wg0 (for server) or client (without the .conf extension, for client).

Users of [email protected] can simply reload the service.

Workaround for some public WiFi/networks seemingly blocking WireGuard connections

Note: This workaround will only be an option if a cellular connection is available on the device.

Some WiFi networks can be configured to actively identify and block Wireguard's handshake thus preventing the initial connection and preventing the establishment of the secure tunnel.

This strategy works for blocking new WireGuard connections but it is useless against existing connections. Therefore, to use WireGuard on such a network, simply connect to the WireGuard peer over cellular before joining the WiFi network thus allowing the handshake to take place before the active blocking can occur. WireGuard will keep this tunnel open as the devices transitions from cellular to WiFi,

Troubleshooting

Routes are periodically reset

Users of NetworkManager should make sure that it is not managing the WireGuard interface(s). For example, create the following configuration file:

/etc/NetworkManager/conf.d/unmanaged.conf

[keyfile]unmanaged-devices=type:wireguard

Broken DNS resolution

When tunneling all traffic through a WireGuard interface, the connection can become seemingly lost after a while or upon new connection. This could be caused by a network manager or DHCP client overwriting /etc/resolv.conf.

By default wg-quick uses resolvconf to register new DNS entries (from the DNS keyword in the configuration file). This will cause issues with network managers and DHCP clients that do not use resolvconf, as they will overwrite /etc/resolv.conf thus removing the DNS servers added by wg-quick.

The solution is to use networking software that supports resolvconf.

Users of NetworkManager should know that it does not use resolvconf by default. It is recommended to use systemd-resolved. If this is undesirable, install openresolv and configure NetworkManager to use it: NetworkManager#Use openresolv.

Adjusting the MTU value

Due to too low MTU (lower than 1280), wg-quick may have failed to create the WireGuard interface. This can be solved by setting the MTU value in WireGuard configuration in Interface section on client.

foo.config

[Interface]Address = 10.200.200.2/24MTU = 1420PrivateKey = PEER_FOO_PRIVATE_KEYDNS = 10.200.200.1

Depending on your network, a lower MTU value can also make your WireGuard connection work.

Key is not the correct length or format

To avoid the following error, put the key value in the configuration file and not the path to the key file.

# wg-quick up wg0

[#] ip link add wg0 type wireguard[#] wg setconf wg0 /dev/fd/63Key is not the correct length or format: `/path/example.key'Configuration parsing error[#] ip link delete dev wg0

Unable to establish a persistent connection behind NAT / firewall

By default, WireGuard peers remain silent while they do not need to communicate, so peers located behind a NAT and/or firewall may be unreachable from other peers until they reach out to other peers themselves (or the connection may time out). Adding PersistentKeepalive = 25 to the [Peer] settings of a peer located behind a NAT and/or firewall can ensure that the connection remains open.

To temporarily set the persistent-keepalive setting via command line, run the following command:

# wg set wg0 peer public_key persistent-keepalive 25

Loop routing

Adding the endpoint IP to the allowed IPs list, the kernel will attempt to send handshakes to said device binding, rather than using the original route. This results in failed handshake attempts.

As a workaround, the correct route to the endpoint needs to be manually added using

# ip route add endpoint_ip via gateway dev network_interface

E.g. for peer B from above in a standard LAN setup:

# ip route add 203.0.113.102 via 192.168.0.1 dev eth0

To make this route persistent, the command can be added as PostUp = ip route ... to the [Interface] section of wg0.conf. However, on certain setups (e.g. using [email protected] in combination with NetworkManager) this might fail on resume. Furthermore, this only works for a static network setup and fails if gateways or devices change (e.g. using Ethernet or Wi-Fi on a laptop).

Using NetworkManager, a more flexible solution is to start WireGuard using a dispatcher script. As root, create

/etc/NetworkManager/dispatcher.d/50-wg0.sh

#!/bin/shcase $2 in up) wg-quick up wg0 ip route add <endpoint ip> via $IP4_GATEWAY dev $DEVICE_IP_IFACE ;; pre-down) wg-quick down wg0 ;;esac

If not already running, start and enable NetworkManager-dispatcher.service. Also make sure that NetworkManager is not managing routes for wg0, see #Routes are periodically reset.

Connection lost after sleep using systemd-networkd

systemd version 253 introduced a change in how network interfaces are reconfigured when resuming from a suspended state[8]. In doing so, network connections managed by systemd-networkd will lose connection to the wireguard interface. Unless a kill switch is configured, this risks exposing the public IP address after resuming from suspension. To fix this, uncomment and change the value to no for ManageForeignRoutingPolicyRules in /etc/systemd/networkd.conf. [9]

Review the systemd-networkd page in full to become informed of any other potential side effects of this change, if any.

See also

• Wikipedia:WireGuard
• Presentations by Jason Donenfeld.
• Mailing list
• Unofficial WireGuard Documentation
• Debian:Wireguard