# Setting up Synapse Simple Antispam (optional, advanced) The playbook can install and configure [synapse-simple-antispam](https://github.com/t2bot/synapse-simple-antispam) for you. See that project's documentation to learn what it does and why it might be useful to you. In short, it lets you fight invite-spam by automatically blocking invitiations from a list of servers specified by you (blacklisting). ## Adjusting the playbook configuration Add the following configuration to your `inventory/host_vars/matrix.DOMAIN/vars.yml` file (adapt to your needs): ```yaml matrix_synapse_ext_spam_checker_synapse_simple_antispam_enabled: true matrix_synapse_ext_spam_checker_synapse_simple_antispam_config_blocked_homeservers: - example.com - another.com ```