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.