matrix-docker-ansible-deploy/docs/configuring-playbook-federation.md

# Controlling Matrix federation (optional)

By default, your server federates with the whole Matrix network.
That is, people on your server can communicate with people on any other Matrix server.


## Federating only with select servers

To make your server only federate with servers of your choosing, add this to your configuration file (`inventory/host_vars/matrix.<your-domain>/vars.yml`):

```yaml
matrix_synapse_federation_domain_whitelist:
- example.com
- another.com
```

If you wish to disable federation, you can do that with an empty list (`[]`), or better yet by completely disabling federation (see below).


## Disabling federation

To completely disable federation, isolating your server from the rest of the Matrix network, add this to your configuration file (`inventory/host_vars/matrix.<your-domain>/vars.yml`):

```yaml
matrix_synapse_federation_enabled: false
```

With that, your server's users will only be able to talk among themselves, but not to anyone who is on another server.