Here you can configure Prosody <a href="https://modules.prosody.im/mod_firewall" target="_blank">mod_firewall</a> module. You can create multiple configuration files bellow, and change their order. Don't hesitate to share your configurations with the community (for example by adding some examples in the plugindocumentation).
Warning: mod_firewall is disabled in the livechat <a href="/admin/plugins/show/peertube-plugin-livechat" target="_blank">pluginsettings</a>, you have to enable it if you want this configuration to be taken into account.
If you can't make it work, you can use the diagnostic tool (there is a button on top of the pluginsettings page), and take a close look on the «Prosody check» section.