Some script-kiddies wrote bot with autoregistration, which generate many flood and can not be banned by expression '*@12jabber.com' (w/o quotes. Expression doesn't work).
Is it something, which i miss in docs, or such functionality (ban by expression) not implemented?
If you want to disallow
If you want to disallow anybody from the server 12jabber.com to join rooms in your MUC service, you can setup something like this:
{acl, jabber12com, {server, "12jabber.com"}}. {access, muc, [{deny, jabber12com}, {allow, all}]}. {modules, [ ... {mod_muc, [ {access, muc}, ... ]}, ... ]}.