Add docs on how to set up Windows clients

README.md

@@ -42,7 +42,7 @@ headscale implements this coordination server.
 | Linux   | Yes                                                                                                               |
 | OpenBSD | Yes                                                                                                               |
 | macOS   | Yes (see `/apple` on your headscale for more information)                                                         |
-| Windows | Yes                                                                                                               |
+| Windows | Yes [docs](./docs/windows-client.md)                                                                              |
 | Android | [You need to compile the client yourself](https://github.com/juanfont/headscale/issues/58#issuecomment-885255270) |
 | iOS     | Not yet                                                                                                           |
 

docs/windows-client.md

@@ -0,0 +1,42 @@
+# Connecting a Windows client
+
+## Goal
+
+This documentation has the goal of showing how a user can use the official Windows [Tailscale](https://tailscale.com) client with `headscale`.
+
+## Add registry keys
+
+To make the Windows client behave as expected and to run well with `headscale`, two registry keys **must** be set:
+
+- `HKLM:\SOFTWARE\Tailscale IPN\UnattendedMode` must be set to `always` to allow Tailscale to run properly in the background
+- `HKLM:\SOFTWARE\Tailscale IPN\LoginURL` must be set to `<YOUR HEADSCALE URL>` to ensure Tailscale contacts the correct control server.
+
+The Tailscale Windows client has been observed to reset its configuration on logout/reboot and these two keys [resolves that issue](https://github.com/tailscale/tailscale/issues/2798).
+
+For a guide on how to edit registry keys, [check out Computer Hope](https://www.computerhope.com/issues/ch001348.htm).
+
+## Installation
+
+Download the [Official Windows Client](https://tailscale.com/download/windows) and install it.
+
+When the installation has finished, start Tailscale and log in (you might have to click the icon in the system tray).
+
+The log in should open a browser Window and direct you to your `headscale` instance.
+
+## Troubleshooting
+
+If you are seeing repeated messages like:
+
+```
+[GIN] 2022/02/10 - 16:39:34 | 200 |    1.105306ms |       127.0.0.1 | POST     "/machine/redacted"
+```
+
+in your `headscale` output, turn on `DEBUG` logging and look for:
+
+```
+2022-02-11T00:59:29Z DBG Machine registration has expired. Sending a authurl to register machine=redacted
+```
+
+This typically means that the register keys above was not set appropriatly.
+
+Ensure they are set correctly, delete Tailscale APP_DATA folder and try to connect again.