website/integrations: Headscale: cleanup (#23107)

Agent-thread: https://sdko.org/internal/thr/ak/019eccd0-37eb-7b40-ab31-46609a646b53
A7k-product: product
A7k-product-repo: 4

Co-authored-by: Agent <gptagent@svc.sdko.net>

website/integrations/networking/headscale/index.md

@@ -8,7 +8,7 @@ import RedirectURI20265Note from "../../\_redirect-uri-2026-5-note.mdx";
 
 ## What is Headscale?
 
-> Headscale is an open source alternative to the Tailscale coordination server and can be self-hosted for a single tailnet. Headscale is a re-implemented version of the Tailscale coordination server, developed independently and completely separate from Tailscale, with its own independent community of users and developers.
+> Headscale is an open source, self-hosted implementation of the Tailscale control server.
 >
 > -- https://headscale.net
 
@@ -33,41 +33,30 @@ To support the integration of Headscale with authentik, you need to create an ap
 
 1. Log in to authentik as an administrator and open the authentik Admin interface.
 2. Navigate to **Applications** > **Applications** and click **New Application** to open the application wizard.
-    - **Application**: provide a descriptive name, an optional group for the type of application, the policy engine mode, and optional UI settings.
+    - **Application**: provide a descriptive name, an optional group for the type of application, the policy engine mode, and optional UI settings. Note the **Slug** value because it will be required later.
     - **Choose a Provider type**: select **OAuth2/OpenID Connect** as the provider type.
     - **Configure the Provider**: provide a name (or accept the auto-provided name), the authorization flow to use for this provider, and the following required configurations.
-        - Note the **Client ID**, **Client Secret**, and **slug** values because they will be required later.
+        - Note the **Client ID** and **Client Secret** values because they will be required later.
         - Add a **Redirect URI** of type `Strict` `Authorization` as `https://headscale.company/oidc/callback`.
         - Select any available signing key.
+        - Leave **Encryption Key** empty.
     - **Configure Bindings** _(optional)_: you can create a [binding](/docs/add-secure-apps/bindings-overview/) (policy, group, or user) to manage the listing and access to applications on a user's **Application Dashboard** page.
 
 3. Click **Submit** to save the new application and provider.
 
 ## Headscale configuration
 
-To support the integration of Headscale with authentik, you'll need to update the `config.yaml` file of your Headscale deployment:
+To support the integration of Headscale with authentik, update the `oidc` section in the Headscale configuration file:
 
 ```yaml showLineNumbers title="/etc/headscale/config.yaml"
 oidc:
-    # Do not start Headscale until it can fetch authentik's OIDC configuration
-    only_start_if_oidc_is_available: true
-    issuer: "https://authentik.company/application/o/<headscale-slug>/"
+    issuer: "https://authentik.company/application/o/<application_slug>/"
     client_id: "<Client ID from authentik>"
-    # There are three ways to configure the client secret (choose one):
-    #
-    # 1. Directly in the config file (not recommended for production):
-    client_secret: "<Client secret from authentik>"
-    #
-    # 2. From a file path (supports environment variables, works with systemd's LoadCredential):
-    # client_secret_path: "${CREDENTIALS_DIRECTORY}/oidc_client_secret"
-    #
-    # 3. From an environment variable:
-    # The HEADSCALE_OIDC_CLIENT_SECRET environment variable will be used automatically if set
-
+    client_secret: "<Client Secret from authentik>"
     # OIDC scopes to request (defaults: "openid", "profile", "email")
     # Additional scopes can be added to request extra user information
     scope: ["openid", "profile", "email", "custom"]
-    # Passed on to the browser login request – used to tweak behaviour for the OIDC provider (optional)
+    # Passed on to the browser login request - used to tweak behaviour for the OIDC provider (optional)
     extra_params:
         domain_hint: acmecorp.net
 
@@ -85,18 +74,17 @@ oidc:
 
     pkce:
         enabled: true
-        method: S256
-
-    # Email Domain Handling:
-    # When strip_email_domain is true: "user@acmecorp.net" becomes username "user"
-    # When strip_email_domain is false: "user@acmecorp.net" becomes username "user.acmecorp.net"
-    strip_email_domain: true
 ```
 
+If you store the client secret outside the configuration file, use Headscale's `client_secret_path` setting or the `HEADSCALE_OIDC_CLIENT_SECRET` environment variable instead of `client_secret`.
+
+Restart Headscale for the configuration changes to take effect.
+
 ## Configuration verification
 
-To verify the integration with Headscale, log out and attempt to log back in using OIDC. When attempting to log in, you'll be redirected to your Headscale installation, which then forwards you to authentik before returning to Headscale, though the exact flow may vary slightly depending on the client platform.
+To confirm that authentik is properly configured with Headscale, open Headscale and sign in with OIDC.
 
 ## Resources
 
 - [Headscale OIDC documentation](https://headscale.net/stable/ref/oidc/#basic-configuration)
+- [Headscale configuration documentation](https://headscale.net/stable/ref/configuration/)