Reverse-proxy

info

Since authentik uses WebSockets to communicate with Outposts, it does not support HTTP/1.0 reverse-proxies. The HTTP/1.0 specification does not officially support WebSockets or protocol upgrades, though some clients may allow it.

If you want to access authentik behind a reverse proxy, there are a few headers that must be passed upstream:

• X-Forwarded-Proto: Tells authentik and Proxy Providers if they are being served over an HTTPS connection.
• X-Forwarded-For: Without this, authentik will not know the IP addresses of clients.
• Host: Required for various security checks, WebSocket handshake, and Outpost and Proxy Provider communication.
• Connection: Upgrade and Upgrade: WebSocket: Required to upgrade protocols for requests to the WebSocket endpoints under HTTP/1.1.

It is also recommended to use a modern TLS configuration and disable SSL/TLS protocols older than TLS 1.3.

If your reverse proxy isn't accessing authentik from a private IP address, trusted proxy CIDRs configuration needs to be set on the authentik server to allow client IP address detection.

The following nginx configuration can be used as a starting point for your own configuration.

# Upstream where your authentik server is hosted.
upstream authentik {
    server <hostname of your authentik server>:9443;
    # Improve performance by keeping some connections alive.
    keepalive 10;
}

# Upgrade WebSocket if requested, otherwise use keepalive
map $http_upgrade $connection_upgrade_keepalive {
    default upgrade;
    ''      '';
}

server {
    # HTTP server config
    listen 80;
    listen [::]:80;
    server_name sso.domain.tld;
    # 301 redirect to HTTPS
    return 301 https://$host$request_uri;
}
server {
    # HTTPS server config
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    server_name sso.domain.tld;

    # TLS certificates
    ssl_certificate /etc/letsencrypt/live/domain.tld/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/domain.tld/privkey.pem;
    add_header Strict-Transport-Security "max-age=63072000" always;

    # Proxy site
    # Location can be set to a subpath if desired, see documentation linked below:
    # https://goauthentik.io/docs/installation/configuration#authentik_web__path
    location / {
        proxy_pass https://authentik;
        proxy_http_version 1.1;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $http_host;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $connection_upgrade_keepalive;
    }
}