filter spam messages based on JID/content

 This module allows for filtering spam messages and subscription requests
 received from remote servers based on lists of known spammer JIDs and/or
 URLs mentioned in spam messages. Traffic classified as spam is rejected
 with an error (and an [info] message is logged) unless the sender is
 subscribed to the recipient's presence. An access rule can be specified
 to control which recipients are subject to spam filtering