Configure a Wireguard interface (wg): Difference between revisions

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WireGuard is a very promising VPN technology available in the community repository since Alpine 3.10.
[https://en.wikipedia.org/wiki/WireGuard WireGuard] multiple platform vpn solution. WireGuard itself is now integrated into the linux kernel since v5.6. Only the userland configuration tools are required.


There are several ways to install and configure an interface.
== Installation  ==


In order to load the WireGuard kernel module, you need a compatible kernel:
The most straightforward method to configure WireGuard is to use the tool <code>wg-quick</code> available in the package {{pkg|wireguard-tools-wg-quick}}.


* linux-lts
Install the meta package {{pkg|wireguard-tools}} to install the necessary WireGuard packages  and {{pkg|iptables}} as follows: {{Cmd|# apk add wireguard-tools iptables}}
* linux-virt


== Bringing up an interface using wg-tools ==
== Configuration ==


The most straightforward method, and the one recommended in WireGuard documentation, is to use <code>wg-quick</code>.
=== Create Server Keys and Interface Config ===


Install wireguard-tools
Create a server private and public key: {{Cmd|<nowiki># wg genkey | tee server.privatekey | wg pubkey > server.publickey</nowiki>}}


apk add wireguard-tools
Then, we create a new config file {{Path|/etc/wireguard/wg0.conf}} using these new keys as follows:{{Cat|/etc/wireguard/wg0.conf|<nowiki>
 
[Interface]
Then load the module
Address = 192.168.2.1/24
 
ListenPort = 45340
modprobe wireguard
PrivateKey = <server private key value> # the key from the previously generated privatekey file
 
PostUp = iptables -A FORWARD -i %i -j ACCEPT; iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE;iptables -A FORWARD -o %i -j ACCEPT
Add it to <code>/etc/modules</code> to automatically load it on boot.
PostDown = iptables -D FORWARD -i %i -j ACCEPT; iptables -t nat -D POSTROUTING -o eth0 -j MASQUERADE;iptables -D FORWARD -o %i -j ACCEPT
 
Then, we need to create a private and a public key:
[Peer]
 
PublicKey = <client public key value> # obtained from client device via wireguard connection setup process
wg genkey | tee privatekey | wg pubkey > publickey
AllowedIPs = 192.168.2.2/32</nowiki>}}
 
Then, we create a new config file <code>/etc/wireguard/wg0.conf</code> using those keys:
 
[Interface]
Address = 10.123.0.1/24
ListenPort = 45340
PrivateKey = SG1nXk2+kAAKnMkL5aX3NSFPaGjf9SQI/wWwFj9l9U4= # the key from the previously generated privatekey file
PostUp = iptables -A FORWARD -i %i -j ACCEPT; iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE;iptables -A FORWARD -o %i -j ACCEPT
PostDown = iptables -D FORWARD -i %i -j ACCEPT; iptables -t nat -D POSTROUTING -o eth0 -j MASQUERADE;iptables -D FORWARD -o %i -j ACCEPT
 
The PostUp and PostDown steps are there to ensure the interface wg0 will accept and forward traffic to eth0. The postrouting and forward to %i is not required, but it will enable "VPN mode" where users can access the internet via this server if desired.
Note that this requires <code>iptables</code> installed and enabled: <code>apk add iptables && rc-update add iptables</code>.
Reference [https://github.com/pirate/wireguard-docs#user-content-config-reference this WireGuard documentation] for information on adding peers to the config file.


To bring up the new interface we use:
The PostUp and PostDown iptable rules forward traffic from the wg0 subnet (192.168.2.1/24) to the lan subnet on interface eth0. Refer to [https://github.com/pirate/wireguard-docs#user-content-config-reference this WireGuard documentation] for information on adding peers to the config file.


wg-quick up wg0
Bring up the new {{ic|wg0}} interface:{{Cmd|# wg-quick up wg0}}


To take it down, we can use <code>wg-quick down wg0</code> which will clean up the interface and remove the iptables rules.
To take it down, we can use <code>wg-quick down wg0</code> which will clean up the interface and remove the iptables rules.
Note: If running in a Docker container, you will need to run with <code>--cap-add=NET_ADMIN</code> to modify your interfaces.
== Bringing up an interface using ifupdown-ng ==


The official documents from WireGuard show examples of how to set up an interface with the use of wg-quick.
{{Note|If running in a Docker container, you will need to run with <code>--cap-add{{=}}NET_ADMIN</code> to modify your interfaces.}}
In this how-to, we are not going to use that utility. We'll use the plain wg command and [https://github.com/ifupdown-ng/ifupdown-ng/blob/master/doc/interfaces-wireguard.scd ifupdown-ng].


apk add wireguard-tools-wg
=== Use with network interfaces ===


Now that all the tools are installed, you can setup the interface.
To enable connecting with Wireguard on boot, open your {{Path|/etc/network/interfaces}} and add this information after your auto other network interfaces as follows:{{Cat|/etc/network/interfaces|<nowiki>...
The setup of your interface config is out of the scope of this document. You should consult the [https://git.zx2c4.com/WireGuard/about/src/tools/man/wg.8 manual page of wg].
auto wg0
iface wg0 inet static
pre-up wg-quick up /etc/wireguard/wg0.conf</nowiki>}}


After you have finished setting up your wgX interface config, you can add it to your <code>/etc/network/interfaces</code>:
=== Service configuration ===


auto wg0
Since Alpine 3.20, {{pkg|wireguard-tools-openrc}} package provides an OpenRC initd service file.
iface wg0 inet static
        requires eth0
        use wireguard
        address 192.168.42.1
        post-up iptables -A FORWARD -i wg0 -j ACCEPT; iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE;iptables -A FORWARD -o wg0 -j ACCEPT
        post-down iptables -D FORWARD -i wg0 -j ACCEPT; iptables -t nat -D POSTROUTING -o eth0 -j MASQUERADE;iptables -D FORWARD -o wg0 -j ACCEPT


This config will automatically:
To use this, install the package:{{Cmd|# apk add wireguard-tools-openrc }}


* bring the WireGuard interface up after the eth0 interface
To use the WireGuard OpenRC script with {{ic|wg-quick.wg0}}, create a symbolic link to it with the configuration name as follows:{{Cmd|# ln -s /etc/init.d/wg-quick /etc/init.d/wg-quick.wg0}}
* assign a config to this interface (which you have previously created)
* setup the interface address and netmask
* add the route once the interface is up
* remove the interface when it goes down
* enable traffic forwarding (the <code>post-up</code> and <code>post-down</code> lines; requires <code>iptables</code>) (note that this is not required unless you want peers to be able to access external resources like the internet)


To start and stop the interface, you execute:
Add the {{ic|wg-quick.wg0}} service to the default runlevel:{{Cmd|# rc-update add wg-quick.wg0}}
To start|stop|restart the [[OpenRC]] service:{{Cmd|# rc-service wg-quick.wg0 start}}


ifup wg0
=== Enable IP Forwarding ===
ifdown wg0


If your interface config is not stored under <code>/etc/wireguard/</code> you need to specify a <code>wireguard-config-path</code> as well.
With a NAT destination rule in place on your router, you should be able connect to the wireguard instance and access the host. However, if you intend for peers to be able to access external resources (including the internet), you will need to enable ip forwarding.


Edit the file {{Path|/etc/sysctl.conf}} or a <code>.conf</code> file under {{Path|/etc/sysctl.d/}} folder add the following line as follows:{{Cat|/etc/sysctl.conf|
net.ipv4.ip_forward {{=}} 1}}


== Enable IP Forwarding ==
Add the sysctl service to run at boot:{{Cmd|# rc-update add sysctl}}


If you intend for peers to be able to access external resources (including the internet), you will need to enable forwarding.
Then either reboot or run {{ic|# sysctl -p /etc/sysctl.conf}} to reload the settings. To ensure forwarding is turned on, run {{ic|# sysctl -a | grep ip_forward}} and ensure <Code>net.ipv4.ip_forward</code> is set to <code>1</code>.
Edit the file <code>/etc/sysctl.conf</code> (or a <code>.conf</code> file under <code>/etc/sysctl.d/</code>) and add the following line.
 
net.ipv4.ip_forward = 1
 
Then either reboot or run <code>sysctl -p /etc/sysctl.conf</code> to reload the settings.
To ensure forwarding is turned on, run <code>sysctl -a | grep ip_forward</code> and ensure <code>net.ipv4.ip_forward</code> is set to <code>1</code>.
To make the change permanent across reboots, you may need to enable the <code>sysctl</code> service: <code>rc-update add sysctl</code>.


In the file {{Path|/etc/conf.d/iptables}}, Change the setting as follows:{{Cat|/etc/conf.d/iptables|...
IPFORWARD{{=}}"yes"}}


== Running with modloop ==
== Running with modloop ==


If you are running from a RAM disk, you can't modify the modloop.
If you are running [[Diskless Mode]] i.e from a RAM disk, you can't modify the modloop.  


You can get around it by unpacking the modloop, mounting the unpacked modules folder, then installing WireGuard.
You can get around it by unpacking the modloop, mounting the unpacked modules folder, then installing WireGuard.  


  #!/bin/sh
  #!/bin/sh
Line 113: Line 83:


You can repack the squash filesystem or put this script in the /etc/local.d/ path so it runs at boot-up.
You can repack the squash filesystem or put this script in the /etc/local.d/ path so it runs at boot-up.
== See also ==
* [https://github.com/pirate/wireguard-docs WireGuard documentation]


[[Category:Networking]]
[[Category:Networking]]

Latest revision as of 16:39, 10 June 2025

WireGuard multiple platform vpn solution. WireGuard itself is now integrated into the linux kernel since v5.6. Only the userland configuration tools are required.

Installation

The most straightforward method to configure WireGuard is to use the tool wg-quick available in the package wireguard-tools-wg-quick.

Install the meta package wireguard-tools to install the necessary WireGuard packages and iptables as follows:

# apk add wireguard-tools iptables

Configuration

Create Server Keys and Interface Config

Create a server private and public key:

# wg genkey | tee server.privatekey | wg pubkey > server.publickey

Then, we create a new config file /etc/wireguard/wg0.conf using these new keys as follows:

Contents of /etc/wireguard/wg0.conf

[Interface] Address = 192.168.2.1/24 ListenPort = 45340 PrivateKey = <server private key value> # the key from the previously generated privatekey file PostUp = iptables -A FORWARD -i %i -j ACCEPT; iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE;iptables -A FORWARD -o %i -j ACCEPT PostDown = iptables -D FORWARD -i %i -j ACCEPT; iptables -t nat -D POSTROUTING -o eth0 -j MASQUERADE;iptables -D FORWARD -o %i -j ACCEPT [Peer] PublicKey = <client public key value> # obtained from client device via wireguard connection setup process AllowedIPs = 192.168.2.2/32

The PostUp and PostDown iptable rules forward traffic from the wg0 subnet (192.168.2.1/24) to the lan subnet on interface eth0. Refer to this WireGuard documentation for information on adding peers to the config file.

Bring up the new wg0 interface:

# wg-quick up wg0

To take it down, we can use wg-quick down wg0 which will clean up the interface and remove the iptables rules.

Note: If running in a Docker container, you will need to run with --cap-add=NET_ADMIN to modify your interfaces.

Use with network interfaces

To enable connecting with Wireguard on boot, open your /etc/network/interfaces and add this information after your auto other network interfaces as follows:

Contents of /etc/network/interfaces

... auto wg0 iface wg0 inet static pre-up wg-quick up /etc/wireguard/wg0.conf

Service configuration

Since Alpine 3.20, wireguard-tools-openrc package provides an OpenRC initd service file.

To use this, install the package:

# apk add wireguard-tools-openrc

To use the WireGuard OpenRC script with wg-quick.wg0, create a symbolic link to it with the configuration name as follows:

# ln -s /etc/init.d/wg-quick /etc/init.d/wg-quick.wg0

Add the wg-quick.wg0 service to the default runlevel:

# rc-update add wg-quick.wg0

To start|stop|restart the OpenRC service:

# rc-service wg-quick.wg0 start

Enable IP Forwarding

With a NAT destination rule in place on your router, you should be able connect to the wireguard instance and access the host. However, if you intend for peers to be able to access external resources (including the internet), you will need to enable ip forwarding.

Edit the file /etc/sysctl.conf or a .conf file under /etc/sysctl.d/ folder add the following line as follows:

Contents of /etc/sysctl.conf

net.ipv4.ip_forward = 1

Add the sysctl service to run at boot:

# rc-update add sysctl

Then either reboot or run # sysctl -p /etc/sysctl.conf to reload the settings. To ensure forwarding is turned on, run # sysctl -a and ensure net.ipv4.ip_forward is set to 1.

In the file /etc/conf.d/iptables, Change the setting as follows:

Contents of /etc/conf.d/iptables

... IPFORWARD="yes"

Running with modloop

If you are running Diskless Mode i.e from a RAM disk, you can't modify the modloop.

You can get around it by unpacking the modloop, mounting the unpacked modules folder, then installing WireGuard. 

#!/bin/sh
apk add squashfs-tools # install squashfs tools to unpack modloop
unsquashfs -d /root/squash /lib/modloop-lts # unpack modloop to root dir
umount /.modloop # unmount existing modloop
mount /root/squash/ /.modloop/ # mount unpacked modloop
apk del wireguard-lts # uninstall previous WireGuard install
apk add wireguard-lts
apk add wireguard-tools

You can repack the squash filesystem or put this script in the /etc/local.d/ path so it runs at boot-up.

See also

Retrieved from "https://wiki.alpinelinux.org/w/index.php?title=Configure_a_Wireguard_interface_(wg)&oldid=30217"