Cloudflare Zero Trust

Tested Versions

Before You Begin

Common Notes

  1. You are required to utilize a unique client id for every client.
  2. The client id on this page is merely an example and you can theoretically use any alphanumeric string.
  3. You should not use the client secret in this example, We strongly recommend reading the Generating Client Secrets guide instead.

Assumptions

This example makes the following assumptions:

  • Cloudflare Team Name: example-team
  • Authelia Root URL: https://auth.example.com
  • Client ID: cloudflare
  • Client Secret: cloudflare_client_secret

Important Note: Cloudflare Zero Trust does not properly URL encode the secret per RFC6749 Appendix B at the time this article was last modified (noted at the bottom). This means you’ll either have to use only alphanumeric characters for the secret or URL encode the secret yourself.

Configuration

Application

Important Note: It is a requirement that the Authelia URL’s can be requested by Cloudflare’s servers. This usually means that the URL’s are accessible to foreign clients on the internet. There may be a way to configure this without accessibility to foreign clients on the internet on Cloudflare’s end but this is beyond the scope of this document.

To configure Cloudflare Zero Trust to utilize Authelia as an OpenID Connect 1.0 Provider:

  1. Visit the Cloudflare Zero Trust Dashboard
  2. Visit Settings
  3. Visit Authentication
  4. Under Login nethods select Add new
  5. Select OpenID Connect
  6. Set the following values:
    1. Name: Authelia
    2. App ID: cloudflare
    3. Client Secret: cloudflare_client_secret
    4. Auth URL: https://auth.example.com/api/oidc/authorization
    5. Token URL: https://auth.example.com/api/oidc/token
    6. Certificate URL: https://auth.example.com/jwks.json
    7. Enable Proof Key for Code Exchange (PKCE)
    8. Add the following OIDC Claims: preferred_username, mail
  7. Click Save

Authelia

The following YAML configuration is an example Authelia client configuration for use with Cloudflare which will operate with the above example:

- id: cloudflare
  description: Cloudflare ZeroTrust
  secret: '$plaintext$cloudflare_client_secret'
  public: false
  authorization_policy: two_factor
  redirect_uris:
    - https://example-team.cloudflareaccess.com/cdn-cgi/access/callback
  scopes:
    - openid
    - profile
    - email
  userinfo_signing_algorithm: none

See Also