conntrack | Program to modify the conntrack tables | Mehr ...
conntrack is a userspace command line program targeted at system administrators. It enables them to view and manage the in-kernel connection tracking state table.
conntrackd | Connection tracking daemon | Mehr ...
Conntrackd can replicate the status of the connections that are currently being processed by your stateful firewall based on Linux. Conntrackd can also run as statistics daemon.