reverse_proxy.md

Using a reverse proxy with Synapse

It is recommended to put a reverse proxy such as nginx, Apache, Caddy, HAProxy or relayd in front of Synapse. One advantage of doing so is that it means that you can expose the default https port (443) to Matrix clients without needing to run Synapse with root privileges.

You should configure your reverse proxy to forward requests to /_matrix or /_synapse/client to Synapse, and have it set the X-Forwarded-For and X-Forwarded-Proto request headers.

You should remember that Matrix clients and other Matrix servers do not necessarily need to connect to your server via the same server name or port. Indeed, clients will use port 443 by default, whereas servers default to port 8448. Where these are different, we refer to the 'client port' and the 'federation port'. See the Matrix specification for more details of the algorithm used for federation connections, and Delegation for instructions on setting up delegation.

NOTE: Your reverse proxy must not canonicalise or normalise the requested URI in any way (for example, by decoding %xx escapes). Beware that Apache will canonicalise URIs unless you specify nocanon.

Let's assume that we expect clients to connect to our server at https://matrix.example.com, and other servers to connect at https://example.com:8448. The following sections detail the configuration of the reverse proxy and the homeserver.

Homeserver Configuration

The HTTP configuration will need to be updated for Synapse to correctly record client IP addresses and generate redirect URLs while behind a reverse proxy.

In homeserver.yaml set x_forwarded: true in the port 8008 section and consider setting bind_addresses: ['127.0.0.1'] so that the server only listens to traffic on localhost. (Do not change bind_addresses to 127.0.0.1 when using a containerized Synapse, as that will prevent it from responding to proxied traffic.)

Optionally, you can also set request_id_header so that the server extracts and re-uses the same request ID format that the reverse proxy is using.

Reverse-proxy configuration examples

NOTE: You only need one of these.

nginx

server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;

    # For the federation port
    listen 8448 ssl http2 default_server;
    listen [::]:8448 ssl http2 default_server;

    server_name matrix.example.com;

    location ~ ^(/_matrix|/_synapse/client) {
        # note: do not add a path (even a single /) after the port in `proxy_pass`,
        # otherwise nginx will canonicalise the URI and cause signature verification
        # errors.
        proxy_pass http://localhost:8008;
        proxy_set_header X-Forwarded-For $remote_addr;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header Host $host;

        # Nginx by default only allows file uploads up to 1M in size
        # Increase client_max_body_size to match max_upload_size defined in homeserver.yaml
        client_max_body_size 50M;
	
	# Synapse responses may be chunked, which is an HTTP/1.1 feature.
	proxy_http_version 1.1;
    }
}

Caddy v2

matrix.example.com {
  reverse_proxy /_matrix/* localhost:8008
  reverse_proxy /_synapse/client/* localhost:8008
}

example.com:8448 {
  reverse_proxy localhost:8008
}

Delegation example:

example.com {
	header /.well-known/matrix/* Content-Type application/json
	header /.well-known/matrix/* Access-Control-Allow-Origin *
	respond /.well-known/matrix/server `{"m.server": "matrix.example.com:443"}`
	respond /.well-known/matrix/client `{"m.homeserver":{"base_url":"https://matrix.example.com"},"m.identity_server":{"base_url":"https://identity.example.com"}}`
}

matrix.example.com {
    reverse_proxy /_matrix/* localhost:8008
    reverse_proxy /_synapse/client/* localhost:8008
}

Apache

<VirtualHost *:443>
    SSLEngine on
    ServerName matrix.example.com

    RequestHeader set "X-Forwarded-Proto" expr=%{REQUEST_SCHEME}
    AllowEncodedSlashes NoDecode
    ProxyPreserveHost on
    ProxyPass /_matrix http://127.0.0.1:8008/_matrix nocanon
    ProxyPassReverse /_matrix http://127.0.0.1:8008/_matrix
    ProxyPass /_synapse/client http://127.0.0.1:8008/_synapse/client nocanon
    ProxyPassReverse /_synapse/client http://127.0.0.1:8008/_synapse/client
</VirtualHost>

<VirtualHost *:8448>
    SSLEngine on
    ServerName example.com

    RequestHeader set "X-Forwarded-Proto" expr=%{REQUEST_SCHEME}
    AllowEncodedSlashes NoDecode
    ProxyPass /_matrix http://127.0.0.1:8008/_matrix nocanon
    ProxyPassReverse /_matrix http://127.0.0.1:8008/_matrix
</VirtualHost>