FreeBSDShield is a DShield.org reporting client for FreeBSD and the ipfw firewall. It allows you to report attempted security breaches to the DShield cooperative firewall logging effort, which in turn helps the Internet Storm Center (and netizens at large) track trends in network security and catch emerging vulnerabilities.
IPsec-Tools is a Linux port of the user-space tools from KAME. It includes libipsec (a library with a PF_KEY implementation), setkey (a tool for manipulating and dumping the kernel Security Policy Database and Security Association Database), and racoon (Internet Key Exchange daemon for automatically keying IPsec connections).
The MiniUPnP project is a library and a daemon. The library is aimed to enable applications to use the capabilities of a UPnP Internet Gateway Device present on the network to forward ports. The daemon adds the UPnP Internet Gateway Device functionality to a NAT gateway running OpenBSD/NetBSD/FreeBSD/Solaris with PF/IPF or Linux 2.4.x/2.6.x with netfilter. One of its most interesting features is to enforce some permissions to allow or deny redirections, bringing some security to UPnP. Newer versions also support the NAT-PMP protocol from Apple.
SOHT (Socket over HTTP Tunneling) allows you to tunnel socket connections through an HTTP proxy. Restrictive firewalls often prohibit all outgoing trafic except for HTTP. This application allows you to tunnel socket connections over the HTTP protocol. This application consists of a server that serves as a proxy and a client which tunnels a socket connection over an HTTP connection to the server. The current server is written in Java, and there are clients in Java and .NET.
Snort2c attempts to be a improved version of snort2pf with some advantages, such as kqueue usage, pf table support, pf ioctl calls, modular design, daemon mode support, whitelist support, and syslog logging. It contains snort2c (a daemon) and mons2c (snort2c's table management tool).
Tableutil is a utility for converting, aggregating, and performing operations (currently unions, differences, complements, and intersections) on lists of IP addresses. Its primary use is to convert files into a format pfctl(8) can read. It can read plain-text files with ranges (188.8.131.52-184.108.40.206), CIDR-style networks (192.168.0.0/24), single addresses (242.242.242.242), or host names (one.two.com). It can also read p2b files, the preferred file-format of PeerGuardian.