What is synchronization mode?
DenyHosts v2.0 and later introduces synchronization mode which allows DenyHosts daemons the ability to transmit denied host data to a central remote server (hosted by denyhosts.net). Additionally, DenyHosts daemons can also receive data that other DenyHosts daemons have sent to the central server. This feature is intended to provide the ability to proactively deny ip addresses that have attacked other users of DenyHosts. That is, each DenyHosts 2.0 (or later) user can benefit from other users of Denyhosts. Similarly each DenyHosts user can benefit other DenyHosts users.