Zentyal (formerly eBox Platform) is a small business server that offers small and medium businesses an affordable and easy-to-use enterprise-level computer network. It can act as a Gateway, Infrastructure Manager, Unified Threat Manager, Office Server, Unified Communication Server, or a combination of these.
ipt-netflow is high performance NetFlow exporting module for Linux kernel (up to 3.x). It is designed for Linux router with heavy network load. This is netfilter/iptables module adding support for NETFLOW target. It is designed to work without conntrack. It supports NetFlow protocols versions 5, 9, and IPFIX. It has accounting for IPv4, IPv6 traffic, and (NEL) NAT translation events.
otonat is a 1:1 NAT implementation for FreeBSD. Unlike other solutions that keep state for individual user connections even for 1:1 NAT, otonat is completely stateless as far as user connections are concerned. This allows it to scale much better and provide protection against misbehaving clients that may consume a lot of server memory by opening too many connections.