Split the delegating documentation out of federate.md and trim it down

docs/delegate.md

@@ -0,0 +1,87 @@
+# Delegation
+
+For a more flexible configuration, you can have `server_name`
+resources (eg: `@user:example.com`) served by a different host and
+port (eg: `synapse.example.com:443`).
+
+Without configuring delegation, the matrix federation will
+expect to find your server via `example.com:8448`. The following methods
+allow you retain a `server_name` of `example.com` so that your user IDs, room
+aliases, etc continue to look like `*:example.com`, whilst having your
+federation traffic routed to a different server (e.g. `synapse.example.com`).
+
+## .well-known delegation
+
+To use this method, you need to be able to alter the
+`server_name` 's https server to serve the `/.well-known/matrix/server`
+URL. Having an active server (with a valid TLS certificate) serving your
+`server_name` domain is out of the scope of this documentation.
+
+The URL `https://<server_name>/.well-known/matrix/server` should
+return a JSON structure containing the key `m.server` like so:
+
+```json
+{
+    "m.server": "<synapse.server.name>[:<yourport>]"
+}
+```
+
+In our example, this would mean that URL `https://example.com/.well-known/matrix/server`
+should return:
+
+```json
+{
+    "m.server": "synapse.example.com:443"
+}
+```
+
+Note, specifying a port is optional. If no port is specified, then it defaults
+to 8448.
+
+Most installations will not need to configure .well-known. However, it can be
+useful in cases where the admin is hosting on behalf of someone else and
+therefore cannot gain access to the necessary certificate. With .well-known,
+federation servers will check for a valid TLS certificate for the delegated
+hostname (in our example: `synapse.example.com`).
+
+## Delegation FAQ
+
+### When do I need delegation?
+
+If your homeserver's APIs are accessible on the default federation port (8448)
+and the domain your `server_name` points to, you do not need any delegation.
+
+For instance, if you registered `example.com` and pointed its DNS A record at a
+fresh server, you could install Synapse on that host, giving it a `server_name`
+of `example.com`, and once a reverse proxy has been set up to proxy all requests
+sent to the port `8448` and serve TLS certificates for `example.com`, you
+wouldn't need any delegation set up.
+
+**However**, if your homeserver's APIs aren't accessible on port 8448 and on the
+domain `server_name` points to, you will need to let other servers know how to
+find it using delegation.
+
+### Do you still recommend against using a reverse proxy on the federation port?
+
+We no longer actively recommend against using a reverse proxy. Many admins will
+find it easier to direct federation traffic to a reverse proxy and manage their
+own TLS certificates, and this is a supported configuration.
+
+See [reverse_proxy.md](reverse_proxy.md) for information on setting up a
+reverse proxy.
+
+### Do I still need to give my TLS certificates to Synapse if I am using a reverse proxy?
+
+This is no longer necessary. If you are using a reverse proxy for all of your
+TLS traffic, then you can set `no_tls: True` in the Synapse config.
+
+In that case, the only reason Synapse needs the certificate is to populate a legacy
+`tls_fingerprints` field in the federation API. This is ignored by Synapse 0.99.0
+and later, and the only time pre-0.99 Synapses will check it is when attempting to
+fetch the server keys - and generally this is delegated via `matrix.org`, which
+is running a modern version of Synapse.
+
+### Do I need the same certificate for the client and federation port?
+
+No. There is nothing stopping you from using different certificates,
+particularly if you are using a reverse proxy.

docs/federate.md

@@ -18,139 +18,6 @@ Once federation has been configured, you should be able to join a room over
 federation. A good place to start is ``#synapse:matrix.org`` - a room for
 Synapse admins.
 
-
-## Delegation
-
-For a more flexible configuration, you can have ``server_name``
-resources (eg: ``@user:example.com``) served by a different host and
-port (eg: ``synapse.example.com:443``). There are two ways to do this:
-
-- adding a ``/.well-known/matrix/server`` URL served on ``https://example.com``.
-- adding a DNS ``SRV`` record in the DNS zone of domain
-  ``example.com``.
-
-Without configuring delegation, the matrix federation will
-expect to find your server via ``example.com:8448``. The following methods
-allow you retain a `server_name` of `example.com` so that your user IDs, room
-aliases, etc continue to look like `*:example.com`, whilst having your
-federation traffic routed to a different server.
-
-### .well-known delegation
-
-To use this method, you need to be able to alter the
-``server_name`` 's https server to serve the ``/.well-known/matrix/server``
-URL. Having an active server (with a valid TLS certificate) serving your
-``server_name`` domain is out of the scope of this documentation.
-
-The URL ``https://<server_name>/.well-known/matrix/server`` should
-return a JSON structure containing the key ``m.server`` like so:
-
-    {
-	    "m.server": "<synapse.server.name>[:<yourport>]"
-    }
-
-In our example, this would mean that URL ``https://example.com/.well-known/matrix/server``
-should return:
-
-    {
-	    "m.server": "synapse.example.com:443"
-    }
-
-Note, specifying a port is optional. If a port is not specified an SRV lookup
-is performed, as described below. If the target of the
-delegation does not have an SRV record, then the port defaults to 8448.
-
-Most installations will not need to configure .well-known. However, it can be
-useful in cases where the admin is hosting on behalf of someone else and
-therefore cannot gain access to the necessary certificate. With .well-known,
-federation servers will check for a valid TLS certificate for the delegated
-hostname (in our example: ``synapse.example.com``).
-
-### DNS SRV delegation
-
-To use this delegation method, you need to have write access to your
-``server_name`` 's domain zone DNS records (in our example it would be
-``example.com`` DNS zone).
-
-This method requires the target server to provide a
-valid TLS certificate for the original ``server_name``.
-
-You need to add a SRV record in your ``server_name`` 's DNS zone with
-this format:
-
-     _matrix._tcp.<yourdomain.com> <ttl> IN SRV <priority> <weight> <port> <synapse.server.name>
-
-In our example, we would need to add this SRV record in the
-``example.com`` DNS zone:
-
-     _matrix._tcp.example.com. 3600 IN SRV 10 5 443 synapse.example.com.
-
-Once done and set up, you can check the DNS record with ``dig -t srv
-_matrix._tcp.<server_name>``. In our example, we would expect this:
-
-    $ dig -t srv _matrix._tcp.example.com
-    _matrix._tcp.example.com. 3600    IN      SRV     10 0 443 synapse.example.com.
-
-Note that the target of a SRV record cannot be an alias (CNAME record): it has to point
-directly to the server hosting the synapse instance.
-
-### Delegation FAQ
-#### When do I need a SRV record or .well-known URI?
-
-If your homeserver listens on the default federation port (8448), and your
-`server_name` points to the host that your homeserver runs on, you do not need an SRV
-record or `.well-known/matrix/server` URI.
-
-For instance, if you registered `example.com` and pointed its DNS A record at a
-fresh server, you could install Synapse on that host,
-giving it a `server_name` of `example.com`, and once [ACME](acme.md) support is enabled,
-it would automatically generate a valid TLS certificate for you via Let's Encrypt
-and no SRV record or .well-known URI would be needed.
-
-**However**, if your server does not listen on port 8448, or if your `server_name`
-does not point to the host that your homeserver runs on, you will need to let
-other servers know how to find it. The way to do this is via .well-known or an
-SRV record.
-
-#### I have created a .well-known URI. Do I also need an SRV record?
-
-No. You can use either `.well-known` delegation or use an SRV record for delegation. You
-do not need to use both to delegate to the same location.
-
-#### Can I manage my own certificates rather than having Synapse renew certificates itself?
-
-Yes, you are welcome to manage your certificates yourself. Synapse will only
-attempt to obtain certificates from Let's Encrypt if you configure it to do
-so.The only requirement is that there is a valid TLS cert present for
-federation end points.
-
-#### Do you still recommend against using a reverse proxy on the federation port?
-
-We no longer actively recommend against using a reverse proxy. Many admins will
-find it easier to direct federation traffic to a reverse proxy and manage their
-own TLS certificates, and this is a supported configuration.
-
-See [reverse_proxy.md](reverse_proxy.md) for information on setting up a
-reverse proxy.
-
-#### Do I still need to give my TLS certificates to Synapse if I am using a reverse proxy?
-
-Practically speaking, this is no longer necessary.
-
-If you are using a reverse proxy for all of your TLS traffic, then you can set
-`no_tls: True` in the Synapse config. In that case, the only reason Synapse
-needs the certificate is to populate a legacy `tls_fingerprints` field in the
-federation API. This is ignored by Synapse 0.99.0 and later, and the only time
-pre-0.99 Synapses will check it is when attempting to fetch the server keys -
-and generally this is delegated via `matrix.org`, which will be running a modern
-version of Synapse.
-
-#### Do I need the same certificate for the client and federation port?
-
-No. There is nothing stopping you from using different certificates,
-particularly if you are using a reverse proxy. However, Synapse will use the
-same certificate on any ports where TLS is configured.
-
 ## Troubleshooting
 
 You can use the [federation tester](