mirror of
https://github.com/element-hq/synapse.git
synced 2024-11-27 03:58:06 +03:00
85d93d003c
This PR just clarifies in the SRV DNS delegation document that there are still cases a user may have to serve files from `.well-known` endpoints, and this may not be a valid case for using SRV delegation. This has caused some confusion in a few cases. Signed-off-by: William Kray <github@williamkray.com>
111 lines
4.9 KiB
Markdown
111 lines
4.9 KiB
Markdown
# Delegation of incoming federation traffic
|
|
|
|
In the following documentation, we use the term `server_name` to refer to that setting
|
|
in your homeserver configuration file. It appears at the ends of user ids, and tells
|
|
other homeservers where they can find your server.
|
|
|
|
By default, other homeservers will expect to be able to reach yours via
|
|
your `server_name`, on port 8448. For example, if you set your `server_name`
|
|
to `example.com` (so that your user names look like `@user:example.com`),
|
|
other servers will try to connect to yours at `https://example.com:8448/`.
|
|
|
|
Delegation is a Matrix feature allowing a homeserver admin to retain a
|
|
`server_name` of `example.com` so that user IDs, room aliases, etc continue
|
|
to look like `*:example.com`, whilst having federation traffic routed
|
|
to a different server and/or port (e.g. `synapse.example.com:443`).
|
|
|
|
## .well-known delegation
|
|
|
|
To use this method, you need to be able to configure the server at
|
|
`https://<server_name>` to serve a file at
|
|
`https://<server_name>/.well-known/matrix/server`. There are two ways to do this, shown below.
|
|
|
|
Note that the `.well-known` file is hosted on the default port for `https` (port 443).
|
|
|
|
### External server
|
|
|
|
For maximum flexibility, you need to configure an external server such as nginx, Apache
|
|
or HAProxy to serve the `https://<server_name>/.well-known/matrix/server` file. Setting
|
|
up such a server is out of the scope of this documentation, but note that it is often
|
|
possible to configure your [reverse proxy](reverse_proxy.md) for this.
|
|
|
|
The URL `https://<server_name>/.well-known/matrix/server` should be configured
|
|
return a JSON structure containing the key `m.server` like this:
|
|
|
|
```json
|
|
{
|
|
"m.server": "<synapse.server.name>[:<yourport>]"
|
|
}
|
|
```
|
|
|
|
In our example (where we want federation traffic to be routed to
|
|
`https://synapse.example.com`, on port 443), this would mean that
|
|
`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.
|
|
|
|
### Serving a `.well-known/matrix/server` file with Synapse
|
|
|
|
If you are able to set up your domain so that `https://<server_name>` is routed to
|
|
Synapse (i.e., the only change needed is to direct federation traffic to port 443
|
|
instead of port 8448), then it is possible to configure Synapse to serve a suitable
|
|
`.well-known/matrix/server` file. To do so, add the following to your `homeserver.yaml`
|
|
file:
|
|
|
|
```yaml
|
|
serve_server_wellknown: true
|
|
```
|
|
|
|
**Note**: this *only* works if `https://<server_name>` is routed to Synapse, so is
|
|
generally not suitable if Synapse is hosted at a subdomain such as
|
|
`https://synapse.example.com`.
|
|
|
|
## SRV DNS record delegation
|
|
|
|
It is also possible to do delegation using a SRV DNS record. However, that is generally
|
|
not recommended, as it can be difficult to configure the TLS certificates correctly in
|
|
this case, and it offers little advantage over `.well-known` delegation.
|
|
|
|
Please keep in mind that server delegation is a function of server-server communication,
|
|
and as such using SRV DNS records will not cover use cases involving client-server comms.
|
|
This means setting global client settings (such as a Jitsi endpoint, or disabling
|
|
creating new rooms as encrypted by default, etc) will still require that you serve a file
|
|
from the `https://<server_name>/.well-known/` endpoints defined in the spec! If you are
|
|
considering using SRV DNS delegation to avoid serving files from this endpoint, consider
|
|
the impact that you will not be able to change those client-based default values globally,
|
|
and will be relegated to the featureset of the configuration of each individual client.
|
|
|
|
However, if you really need it, you can find some documentation on what such a
|
|
record should look like and how Synapse will use it in [the Matrix
|
|
specification](https://matrix.org/docs/spec/server_server/latest#resolving-server-names).
|
|
|
|
## 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.
|
|
|
|
### Should I use a reverse proxy for federation traffic?
|
|
|
|
Generally, using a reverse proxy for both the federation and client traffic is a good
|
|
idea, since it saves handling TLS traffic in Synapse. See
|
|
[the reverse proxy documentation](reverse_proxy.md) for information on setting up a
|
|
reverse proxy.
|