Authelia Get started

Caddy

Caddy is a reverse proxy supported by Authelia.

Authelia offers integration support for the official forward auth integration method Caddy provides, we don’t officially support any plugin that supports this though we don’t specifically prevent such plugins working and there may be plugins that work fine provided they support the forward authentication specification correctly.

Important: When using these guides, it’s important to recognize that we cannot provide a guide for every possible method of deploying a proxy. These guides show a suggested setup only, and you need to understand the proxy configuration and customize it to your needs. To-that-end, we include links to the official proxy documentation throughout this documentation and in the See Also section.

Get started

It’s strongly recommended that users setting up Authelia for the first time take a look at our Get started guide. This takes you through various steps which are essential to bootstrapping Authelia.

Requirements

You need the following to run Authelia with Caddy:

Trusted Proxies

Important: You should read the Forwarded Headers section and this section as part of any proxy configuration. Especially if you have never read it before.

Important: The included example is NOT meant for production use. It’s used expressly as an example to showcase how you can configure multiple IP ranges. You should customize this example to fit your specific architecture and needs. You should only include the specific IP address ranges of the trusted proxies within your architecture and should not trust entire subnets unless that subnet only has trusted proxies and no other services.

Caddy by default doesn’t trust any other proxies and removes potentially fabricated headers that are likely to lead to security issues, and it is difficult to configure this incorrectly. This is an important security feature that is common with proxies with good security practices.

You should read the Caddy Trusted Proxies Documentation as part of configuring this. It’s important to ensure you take the time to configure this carefully and correctly.

In the example, we have a commented trusted_proxies directive, which shows an example of adding the following networks to the trusted proxy list in Caddy:

  • 10.0.0.0/8
  • 172.16.0.0/12
  • 192.168.0.0/16
  • fc00::/7

Assumptions and Adaptation

This guide makes a few assumptions. These assumptions may require adaptation in more advanced and complex scenarios. We can not reasonably have examples for every advanced configuration option that exists. Some of these values can automatically be replaced with documentation variables.

The following are the assumptions we make:

  • Deployment Scenario:
    • Single Host
    • Authelia is deployed as a Container with the container name authelia on port 9091
    • Proxy is deployed as a Container on a network shared with Authelia
  • The above assumption means that Authelia should be accessible to the proxy on http://authelia:9091 and as such:
    • You will have to adapt all instances of the above URL to be https:// if Authelia configuration has a TLS key and certificate defined
    • You will have to adapt all instances of authelia in the URL if:
      • you’re using a different container name
      • you deployed the proxy to a different location
    • You will have to adapt all instances of 9091 in the URL if:
      • you have adjusted the default port in the configuration
    • You will have to adapt the entire URL if:
      • Authelia is on a different host to the proxy
  • All services are part of the example.com domain:
    • This domain and the subdomains will have to be adapted in all examples to match your specific domains unless you’re just testing or you want to use that specific domain

Implementation

Caddy utilizes the ForwardAuth Authz implementation. The associated Metadata should be considered required.

The examples below assume you are using the default Authz Endpoints Configuration or one similar to the following minimal configuration:

configuration.yml 
server:
  endpoints:
    authz:
      forward-auth:
        implementation: 'ForwardAuth'

The examples below also assume you are using the modern Session Configuration which includes the domain, authelia_url, and default_redirection_url as a subkey of the session.cookies key as a list item. Below is an example of the modern configuration as well as the legacy configuration for context.

configuration.yml 
session:
  cookies:
    - domain: 'example.com'
      authelia_url: 'https://auth.example.com'
      default_redirection_url: 'https://www.example.com'
configuration.yml 
default_redirection_url: 'https://www.example.com'
session:
  domain: 'example.com'

Configuration

Below you will find commented examples of the following configuration:

  • Authelia Portal
  • Protected Endpoint (Nextcloud)

Basic examples

This example is the preferred example for integration with Caddy. There is an advanced example but we strongly urge anyone who needs to use this for a particular reason to either reach out to us or Caddy for support to ensure the basic example covers your use case in a secure way.

Subdomain 

## Uncomment & adjust the following line to configure specific ranges which should be considered as trustworthy.
## It is important to read the following document before enabling this section:
##     https://www.authelia.com/integration/proxies/caddy/#trusted-proxies
# trusted_proxies 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16 fc00::/7

# Authelia Portal.
auth.example.com {
        reverse_proxy authelia:9091
}

# Protected Endpoint.
nextcloud.example.com {
        forward_auth authelia:9091 {
                uri /api/authz/forward-auth
                ## The following commented line is for configuring the Authelia URL in the proxy. We strongly suggest
                ## this is configured in the Session Cookies section of the Authelia configuration.
                # uri /api/authz/forward-auth?authelia_url=https://auth.example.com/
                copy_headers Remote-User Remote-Groups Remote-Email Remote-Name
        }

        reverse_proxy nextcloud:80
}

Subpath

Important: In order to use a subpath, you must also update your Authelia server address configuration to listen on the new endpoint.

Caddyfile 
## Uncomment & adjust the following line to configure specific ranges which should be considered as trustworthy.
## It is important to read the following document before enabling this section:
##     https://www.authelia.com/integration/proxies/caddy/#trusted-proxies
# trusted_proxies 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16 fc00::/7

example.com {
        # Authelia Portal.
        @authelia path /authelia /authelia/*
        handle @authelia {
                reverse_proxy authelia:9091
        }

        # Protected Endpoint.
        @nextcloud path /nextcloud /nextcloud/*
        handle @nextcloud {
                forward_auth authelia:9091 {
                        uri /api/authz/forward-auth?authelia_url=https://example.com/authelia/
                        copy_headers Remote-User Remote-Groups Remote-Email Remote-Name
                }

                reverse_proxy nextcloud:80
        }
}

Advanced examples

Removing the Authelia Session Header

Some users may wish to prevent the Authelia session cookie from reaching the backend. It’s theoretically possible to remove that value from the Cookie header. While this is untested, it’s likely the following example, which includes a header_up directive will remove that value from the Cookie header provided the configured name for the cookie is authelia_session:

nextcloud.example.com {
        forward_auth authelia:9091 {
                uri /api/authz/forward-auth
                copy_headers Remote-User Remote-Groups Remote-Email Remote-Name
        }

        reverse_proxy nextcloud:80 {
                header_up Cookie "authelia_session=[^;]+" "authelia_session=_"
        }
}

Explicit Forward Auth

The advanced example allows for more flexible customization, however the basic example should be preferred in most situations. If you are unsure of what you’re doing please don’t use this method.

Important: Making a mistake when configuring the advanced example could lead to authentication bypass or errors.

Caddyfile 
## Uncomment & adjust the following line to configure specific ranges which should be considered as trustworthy.
## It is important to read the following document before enabling this section:
##     https://www.authelia.com/integration/proxies/caddy/#trusted-proxies
# trusted_proxies 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16 fc00::/7

# Authelia Portal.
auth.example.com {
        reverse_proxy authelia:9091
}

# Protected Endpoint.
nextcloud.example.com {
        reverse_proxy authelia:9091 {
                method GET
                rewrite "/api/authz/forward-auth?authelia_url=https://auth.example.com/"

                header_up X-Forwarded-Method {method}
                header_up X-Forwarded-URI {uri}

                ## If the auth request:
                ##   1. Responds with a status code IN the 200-299 range.
                ## Then:
                ##   1. Proxy the request to the backend.
                ##   2. Copy the relevant headers from the auth request and provide them to the backend.
                @good status 2xx
                handle_response @good {
                        request_header Remote-User {http.reverse_proxy.header.Remote-User}
                        request_header Remote-Groups {http.reverse_proxy.header.Remote-Groups}
                        request_header Remote-Email {http.reverse_proxy.header.Remote-Email}
                        request_header Remote-Name {http.reverse_proxy.header.Remote-Name}
                }
        }

        reverse_proxy nextcloud:80
}

See Also

Last updated on October 5, 2024
Edit this page on GitHub
Prev
Forwarded Headers
Next
Envoy