Auto ban anonymous IP:

* New settings: "Ban anonymous user's IP when user is banned from a chatroom":
  * if enabled, every time a streamer bans an anonymous user, it will ban its IP on the chat server,
  * banned IPs are logged on disk, so server's admin can use them to feed fail2ban (for example),
  * option disabled by default, because could be used to create trapped-rooms on public servers

prosody-modules/mod_muc_ban_ip/README.markdown

@@ -0,0 +1,63 @@
+---
+labels:
+- 'Stage-Alpha'
+summary: Ban users from chatrooms by their IP address
+...
+
+Note: this is a slightly modified version: the log level for IP bans is
+set to info, instead of debug.
+So we can use external tools (fail2ban for example) to block IPs more widely.
+
+Introduction
+============
+
+One frequent complaint about XMPP chatrooms (MUCs) compared to IRC is
+the inability for a room admin to ban a user based on their IP address.
+This is because an XMPP user is not identified on the network by their
+IP address, only their JID.
+
+This means that it is possible to create a new account (usually quite
+easily), and rejoin the room that you were banned from.
+
+This module allows the **user's** server to enforce bans by IP address,
+which is very desirable for server admins who want to prevent their
+server being used for spamming and abusive behaviour.
+
+Details
+=======
+
+An important point to note is that this module enforces the IP ban on
+the banned user's server, not on the MUC server. This means that:
+
+-   The user's server MUST have this module loaded, however -
+-   The module works even when the MUC is on a different server to the
+    user
+-   The MUC server does not need this module (it only needs to support
+    the [standard ban
+    protocol](http://xmpp.org/extensions/xep-0045.html#ban))
+-   The module works for effectively banning [anonymous
+    users](http://prosody.im/doc/anonymous_logins)
+
+Also note that IP bans are not saved permanently, and are reset upon a
+server restart.
+
+Configuration
+=============
+
+There is no extra configuration for this module except for loading it.
+Remember... do not load it on the MUC host, simply add it to your global
+`modules_enabled` list, or under a specific host like:
+
+``` lua
+VirtualHost "anon.example.com"
+  authentication = "anonymous"
+  modules_enabled = { "muc_ban_ip" }
+```
+
+Compatibility
+=============
+
+  ----- --------------
+  0.9   Works
+  0.8   Doesn't work
+  ----- --------------