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/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/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.
