With conntrack-tools you can setup a High Availability cluster and synchronize conntrack state between multiple firewalls. The conntrack-tools package contains two programs: - conntrack: the command line interface to interact with the connection tracking system. - conntrackd: the connection tracking userspace daemon that can be used to deploy highly available GNU/Linux firewalls and collect statistics of the firewall use. conntrack is used to search, list, inspect and maintain the netfilter connection tracking subsystem of the Linux kernel. Using conntrack, you can dump a list of all currently tracked connections, delete connections from the state table, and even add new ones. In addition, you can also monitor connection tracking events, e.g. show an event message per newly established connection.