+++
date = 2023-10-11
title = "Self-Hosting Authelia"
description = ""
draft = false
+++

# Overview

[Authelia](https://www.authelia.com/) is an open-source authentication
service that allows you to place a portal between end users on the
internet and self-hosted services on your server.

You can require one factor (username+password) or two factor
authentication for any such user before allowing them to access a
specific service on your domain.

This guide will walk through a standard installation of Authelia for
`example.com`, using `auth.example.com` as
Authelia\'s authentication domain and `teddit.example.com` as
the website we want to protect behind the authentication portal.

# Prerequisites

This guide assumes you have the following already set-up:

-   A registered domain with DNS pointing to your server.
-   A subdomain for Authelia (`auth.example.com`) and a
    subdomain to protect via Authelia (`app.example.com`).
-   A working Nginx web server.
-   Docker and docker-compose installed.

# Installation

This guide will walk through each installation step one-by-one, starting
with the container and finishing by cleaning up external access via an
Nginx reverse proxy.

## Docker-Compose

To start, create a directory for Authelia and create a
`docker-compose.yml` file.

```sh
mkdir ~/authelia
nano ~/authelia/docker-compose.yml
```

Within this file, paste the following content. If you prefer a different
local port, modify the port on the left side of the colon on the
`9091:9091` line. Be sure to modify the `TZ`
variable to your timezone.

``` yml
version: '3.3'

services:
  authelia:
    image: authelia/authelia
    container_name: authelia
    volumes:
      - ./config:/config
    ports:
      - 9091:9091
    environment:
      - TZ=America/Chicago
```

Start the container with docker-compose:

```sh
sudo docker-compose up -d
```

After the first start, the container will automatically exit and require
you to modify the app\'s configuration files before continuing. Read on
to learn more.

## Authelia Configuration

To configure Authelia before we restart the container, we need to open
the `config` directory and modify the files. Start by editing
the `configuration.yml` file, where all of Authelia\'s
settings are stored.

My personal preference is to copy the original configuration file to a
backup file and edit a fresh copy.

```sh
sudo cp ~/authelia/config/configuration.yml ~/authelia/config/configuration.yml.bk
sudo nano ~/authelia/config/configuration.yml
```

Within the blank `configuration.yml` file, paste the
following information. You will need to make quite a few updates, so be
sure to read each line carefully and modify as necessary.

The major required changes are:

-   Any instances of `example.com` should be replaced by your
    domain.
-   `jwt_secret` - Use the `pwgen 40 1` command to
    generate a secret for yourself.
-   `access_control` - Set the Authelia domain to bypass
    here, as well as any subdomains you want to protect.
-   `session` \> `secret` - Use the
    `pwgen 40 1` command to generate a secret for yourself.
-   `regulation` - Set the variables here to restrict login
    attempts and bans.
-   `storage` \> `encryption_key` - Use the
    `pwgen 40 1` command to generate a secret for yourself.
-   `smtp` - If you have access to an SMTP service, set up
    the information here to active outgoing emails.

``` yml
# yamllint disable rule:comments-indentation
---
###############################################################################
#                           Authelia Configuration                            #
###############################################################################

theme: dark 
jwt_secret: aiS5iedaiv6eeVaideeLeich5roo6ohvaf3Vee1a # pwgen 40 1

default_redirection_url: https://example.com

server:
  host: 0.0.0.0
  port: 9091
  path: ""
  read_buffer_size: 4096
  write_buffer_size: 4096
  enable_pprof: false
  enable_expvars: false
  disable_healthcheck: false
  tls:
    key: ""
    certificate: ""

log:
  level: debug

totp:
  issuer: example.com
  period: 30
  skew: 1

authentication_backend:
  disable_reset_password: false
  refresh_interval: 5m
  file:
    path: /config/users_database.yml
    password:
      algorithm: argon2id
      iterations: 1
      key_length: 32
      salt_length: 16
      memory: 1024
      parallelism: 8

access_control:
  default_policy: deny
  rules:
    - domain:
        - "auth.example.com"
      policy: bypass
    - domain: "teddit.example.com"
      policy: one_factor

session:
  name: authelia_session
  secret: aiS5iedaiv6eeVaideeLeich5roo6ohvaf3Vee1a # pwgen 40 1
  expiration: 3600
  inactivity: 300
  domain: example.com

regulation:
  max_retries: 5
  find_time: 10m
  ban_time: 12h

storage:
  local:
    path: /config/db.sqlite3 
  encryption_key: aiS5iedaiv6eeVaideeLeich5roo6ohvaf3Vee1a # pwgen 40 1

notifier:
  disable_startup_check: true
  smtp:
    username: user@example.com
    password: password
    host: smtp.example.com
    port: 465
    sender: user@example.com
    identifier: example.com
    subject: "[Authelia] {title}"
    startup_check_address: user@example.com
    disable_require_tls: false
    disable_html_emails: true
    tls:
      skip_verify: false
      minimum_version: TLS1.2
...
```

## Authelia Users

Next, create the users file for authentication.

```sh
sudo nano ~/authelia/config/users_database.yml
```

Within the file, you will need to create an entry for each user that
needs access to Authelia. The `my_username` entry will be the
username used on the login page.

To generate the password, go to [Argon2 Hash
Generator](https://argon2.online), generate a random salt, and make sure
the rest of the settings match the `authentication_backend`
section of `configuration.yml` file.

``` yaml
users:
  my_username:
    displayname: "My User"
    # Generated at https://argon2.online/ -- match the settings in 
    # the `authentication_backend` section of configuration.yml
    password: "" 
    email: email@example.com
    groups:
      - admins
      - dev
```

Once the app is configured, restart the container from scratch.

```sh
cd ~/authelia
sudo docker-compose down && sudo docker-compose up -d
```

## Nginx: Authelia Domain

Once the container is running and configured, the final step is to
configure external access to the server via Nginx reverse proxy.

Start by creating the Authelia domain.

```sh
sudo nano /etc/nginx/sites-available/auth
```

Within this file, paste the following information and be sure to update
`example.com` to your domain. Make sure the
`$upstream_authelia` variable matches the location of your
Authelia container.

``` conf
server {
    if ($host ~ ^[^.]+\.example\.com$) {
        return 301 https://$host$request_uri;
    }

    listen [::]:80;
    listen 80;
    server_name auth.example.com;
    return 404;
}

server {
    listen [::]:443 ssl http2;
    listen 443 ssl http2;
    server_name auth.example.com;
    access_log  /var/log/nginx/auth.access.log;
    error_log   /var/log/nginx/auth.error.log;

    ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
    include /etc/letsencrypt/options-ssl-nginx.conf;
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;

    location / {
        set $upstream_authelia http://127.0.0.1:9091;
        proxy_pass $upstream_authelia;
        client_body_buffer_size 128k;

        proxy_next_upstream error timeout invalid_header http_500 http_502 http_503;

        send_timeout 5m;
        proxy_read_timeout 360;
        proxy_send_timeout 360;
        proxy_connect_timeout 360;

        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-Forwarded-Host $http_host;
        proxy_set_header X-Forwarded-Uri $request_uri;
        proxy_set_header X-Forwarded-Ssl on;
        proxy_redirect  http://  $scheme://;
        proxy_http_version 1.1;
        proxy_set_header Connection "";
        proxy_cache_bypass $cookie_session;
        proxy_no_cache $cookie_session;
        proxy_buffers 64 256k;
    }

}
```

Next, symlink the file and restart Nginx. If there are errors, be sure
to resolve those before moving on.

```sh
sudo ln -s /etc/nginx/sites-available/auth /etc/nginx/sites-enabled/auth
sudo systemctl restart nginx.service
```

## Nginx: Protected Domain(s)

Now that Authelia is accessible externally, you need to configure the
domain you intend to protect with Authelia. In this example, I\'m
protecting `teddit.example.com`.

Similar to the process above, paste the content and update the relevant
variables.

```sh
sudo nano /etc/nginx/sites-available/teddit
```

``` conf
server {
    if ($host ~ ^[^.]+\.example\.com$) {
        return 301 https://$host$request_uri;
    }

    listen [::]:80;
    listen 80;
    server_name teddit.example.com;
    return 404;
}

server {
    listen [::]:443 ssl http2;
    listen 443 ssl http2;
    server_name teddit.example.com;
    access_log  /var/log/nginx/teddit.access.log;
    error_log   /var/log/nginx/teddit.error.log;

    add_header X-Content-Type-Options "nosniff";
    add_header X-XSS-Protection "1; mode=block";
    add_header X-Frame-Options "DENY";
    add_header Strict-Transport-Security "max-age=63072000; includeSubDomains";
    add_header Referrer-Policy "no-referrer";

    ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
    include /etc/letsencrypt/options-ssl-nginx.conf;
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem;

    location /authelia {
        internal;
        set $upstream_authelia http://127.0.0.1:9091/api/verify;
        proxy_pass_request_body off;
        proxy_pass $upstream_authelia;
        proxy_set_header Content-Length "";

        proxy_next_upstream error timeout invalid_header http_500 http_502 http_503;
        client_body_buffer_size 128k;
        proxy_set_header Host $host;
        proxy_set_header X-Original-URL $scheme://$http_host$request_uri;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $remote_addr;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-Forwarded-Host $http_host;
        proxy_set_header X-Forwarded-Uri $request_uri;
        proxy_set_header X-Forwarded-Ssl on;
        proxy_redirect  http://  $scheme://;
        proxy_http_version 1.1;
        proxy_set_header Connection "";
        proxy_cache_bypass $cookie_session;
        proxy_no_cache $cookie_session;
        proxy_buffers 4 32k;

        send_timeout 5m;
        proxy_read_timeout 240;
        proxy_send_timeout 240;
        proxy_connect_timeout 240;
    }

    location / {
        set $upstream_teddit http://127.0.0.1:8686;
        proxy_pass $upstream_teddit;

        auth_request /authelia;
        auth_request_set $target_url https://$http_host$request_uri;
        auth_request_set $user $upstream_http_remote_user;
        auth_request_set $email $upstream_http_remote_email;
        auth_request_set $groups $upstream_http_remote_groups;
        proxy_set_header Remote-User $user;
        proxy_set_header Remote-Email $email;
        proxy_set_header Remote-Groups $groups;

        error_page 401 =302 https://auth.example.com/?rd=$target_url;

        client_body_buffer_size 128k;

        proxy_next_upstream error timeout invalid_header http_500 http_502 http_503;

        send_timeout 5m;
        proxy_read_timeout 360;
        proxy_send_timeout 360;
        proxy_connect_timeout 360;

        proxy_set_header Host $host;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection upgrade;
        proxy_set_header Accept-Encoding gzip;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-Forwarded-Host $http_host;
        proxy_set_header X-Forwarded-Uri $request_uri;
        proxy_set_header X-Forwarded-Ssl on;
        proxy_redirect  http://  $scheme://;
        proxy_http_version 1.1;
        proxy_set_header Connection "";
        proxy_cache_bypass $cookie_session;
        proxy_no_cache $cookie_session;
        proxy_buffers 64 256k;
    }
}
```

Same as before, symlink the file and restart Nginx.

```sh
sudo ln -s /etc/nginx/sites-available/teddit /etc/nginx/sites-enabled/teddit
sudo systemctl restart nginx.service
```

# Results

When visiting the protected domain, you will now be redirected to your
authentication domain and presented with the Authelia login portal.

![Authelia
Portal](https://img.cleberg.net/blog/20231010-authelia/authelia_portal.png)

Once you\'ve successfully authenticated, you can visit your
authentication domain directly and see that you\'re currently
authenticated to any domain protected by Authelia.

![Authelia
Success](https://img.cleberg.net/blog/20231010-authelia/authelia_success.png)