LFT (Layer Four Traceroute) is a sort of "traceroute" that often works much faster than the commonly-used Van Jacobson method and goes through many configurations of packet-filter based firewalls. More importantly, LFT implements numerous other features, including TCP, UDP, or ICMP-based traces, AS number lookups through several reliable sources, loose source routing, netblock name lookups, and more. LFT also distinguishes between layer-4 protocols, which make its statistics slightly more realistic, and gives a savvy user the ability to trace protocol routes, not just layer-3 hops.
FrazierWall Linux is a single floppy distribution Linux firewall that is based on the Linux Router Project. It is designed for use with ethernet base internet connections (such as cable modems or xDSL lines). It allows you to share such a connection with several other computers on a LAN. It is easy to setup and maintain, and is available in a Linux configurable software version.
NetGuard is intended to be a complete, embedded firewall solution. It is based on the Debian GNU/Linux operating system, and uses iptables to effectively manage your home or corporate LAN. It's designed to run on a wrap router board, which is hardware that can be run with no fan, no noise, and less power current. NetGuard can be also run on an old PC using the generic PC version.
Nagios is a host, service, and network monitoring system that will watch your network and alert you to problems before your clients or end-users do. The system runs checks on hosts and services that you specify using plugins that return status information to Nagios. When problems are encountered, the system will send notifications to system administrators so that they can take action on the problem. The JumpBox for Nagios gives you a head start to using the system. It eliminates the complexity involved in getting the application installed, and allows you to focus on the configuration for your specific environment. Since Nagios is based on plugins, depending on what you want to do this will vary in complexity.
Xtradius is a radius server that permits you to handle user authentication and accounting request via external scripts. You can handle script requests for user accounting, user authentication, NAS start and NAS stop packets. You can also write additional information into the NAS detail logfile. Parameters to scripts are passed via command line options or environment variables, making it very simple to implement SQL-based user accounting, authentication and account expiration. It is also compatible with "standard" cistron radius server.
Dr.Morena is a tool to confirm the rule configuration of a firewall. It inspects all the firewall rules that are currently in effect, and tests these rules by sending various kinds of test packets through the firewall. This allows you to confirm that the rules that you intend to be in effect are actually in effect.
Trustix™ Enterprise Firewall is a WYSIWYG firewall for iptables. It provides drag and drop security policy deployment and allows you to visualise DMZs, integrate branch offices with 3DES encrypted VPN tunnels, accelerate Internet access times with proxy caching server, and authenticate remote workers with PKI X.509 certificates. The unique GUI also allows you to manage traffic for all your zones (up to 24) as well as port forwarding and network address translation (NAT).