Configure a Wireguard interface (wg): Difference between revisions

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(The example for the ifupdown section caused a RTNETLINK answers: File exists an could be simplified since the introduction of ifupdown-ng in alpine 3.13.0 which has a wireguard executor)
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WireGuard is a very promising VPN technology and available since Alpine 3.10 in the community repository.
WireGuard is a very promising VPN technology available in the community repository since Alpine 3.10


There are several ways to install and configure an interface.
There are several ways to install and configure an interface.
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  PostDown = iptables -D FORWARD -i %i -j ACCEPT; iptables -t nat -D POSTROUTING -o eth0 -j MASQUERADE;iptables -D 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 through this server if desired. Reference this WireGuard documentation for information on adding Peers to the config file.
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. Reference this WireGuard documentation for information on adding peers to the config file.


To bring up the new interface we can just use  
To bring up the new interface we use  


  wg-quick up wg0
  wg-quick up wg0


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


The official documents from wireguard will show examples of how to setup an interface with the use of wg-quick.
The official documents from wireguard show examples of how to set up an interface with the use of wg-quick.
In this howto we are not going to use this utility but are going to use plain wg command and [https://github.com/ifupdown-ng/ifupdown-ng/blob/master/doc/interfaces-wireguard.scd ifupdown-ng].
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
  apk add wireguard-tools-wg


Now that you have all the tools installed we can setup the interface.
Now that all the tools are installed, you can setup the interface.
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].
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].


After you have finished setting up your wgX interface config you can add it to your /etc/network/interfaces:
After you have finished setting up your wgX interface config, you can add it to your /etc/network/interfaces:


  auto wg0
  auto wg0
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         address 192.168.42.1
         address 192.168.42.1


This config automatically will:
This config will automatically:
   
   
* bring the wireguard interface up after the eth0 interface
* bring the wireguard interface up after the eth0 interface
* assign a config to this interface (which you have previously created)
* assign a config to this interface (which you have previously created)
* setup the interface address and netmask
* setup the interface address and netmask
* add the route ones the interface is up
* add the route once the interface is up
* remove the interface when it goes down
* remove the interface when it goes down


To start the interface and stop it you can execute:
To start and stop the interface, you execute:


  ifup wg0
  ifup wg0
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== Running with modloop ==
== Running with modloop ==
If you are running from a RAM disk you can't modify the modloop.
If you are running from a RAM disk, you can't modify the modloop.


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


  #!/bin/sh
  #!/bin/sh
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  apk add wireguard-tools
  apk add wireguard-tools


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


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

Revision as of 17:18, 23 July 2021

WireGuard is a very promising VPN technology available in the community repository since Alpine 3.10

There are several ways to install and configure an interface.

In order to load the wireguard kernel module, you need a compatible kernel:

  • linux-lts
  • linux-virt

Bringing up an interface using wg-tools

The most straightforward method, and the one recommended in WireGuard documentation, is to use wg-quick.

Install wireguard-tools

apk add wireguard-tools

Then load the module

modprobe wireguard

Add it to /etc/modules to automatically load it on boot.

Then we need to create a private and public key

wg genkey | tee privatekey | wg pubkey > publickey

Then we create a new config file /etc/wireguard/wg0.conf 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. Reference this WireGuard documentation for information on adding peers to the config file.

To bring up the new interface we use

wg-quick up wg0

To take it down, we can use wg-quick down wg0 which will clean up the interface and remove the ip table rules. Note: If running in a Docker container, you will need to run with --cap-add=NET_ADMIN 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. In this how-to, we are not going to use that utility. We'll use the plain wg command and ifupdown-ng.

apk add wireguard-tools-wg

Now that all the tools are installed, you can setup the interface. The setup of your interface config is out of the scope of this document. You should consult the manual page of wg.

After you have finished setting up your wgX interface config, you can add it to your /etc/network/interfaces:

auto wg0
iface wg0 inet static
       requires eth0
       use wireguard
       address 192.168.42.1

This config will automatically:

  • bring the wireguard interface up after the eth0 interface
  • 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

To start and stop the interface, you execute:

ifup wg0
ifdown wg0

If your interface config is not stored under /etc/wireguard you need to specify a wireguard-config-path as well.

Running with modloop

If you are running 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.