What are the conntrack-tools?
The conntrack-tools are a set of free software userspace tools for Linux that allow system administrators interact with the Connection Tracking System, which is the module that provides stateful packet inspection for iptables. The conntrack-tools are the userspace daemon conntrackd and the command line interface conntrack.
Why use the conntrack-tools?
The userspace daemon conntrackd can be used to enable high availability of cluster-based stateful firewalls and to collect statistics of the stateful firewall use (although ulogd is the preferred option for logging). The command line interface conntrack provides a more flexible interface than the traditional /proc/net/nf_conntrack interface.