I'd like to turn off federation

Issue

• Need to turn off federation, which is on by default.

Environment

• Element On-Premise Installer

Resolution

Add an empty federation_domain_whitelist. To do this, add the following in a .yml file in the Synapse config folder:

federation_domain_whitelist: []

See https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html?highlight=federation#federation for further details.

N.B. we recommend also firewalling your federation listener to limit inbound federation traffic as early as possible, rather than relying purely on this application-layer restriction. If not specified, the default is to whitelist everything.

Root Cause

Federation is on by default.