gbrctl is a GNOME utility to configure the Linux Ethernet Bridging code as found in Linux kernels version 2.3.47 and higher, and patched 2.2.x kernels. It features fast and easy bridge and port editing and a stack window, displaying images of your active bridges with 'LEDs' displaying the current port statuses.
Gibraltar is a Debian GNU/Linux-based router/firewall distribution, fully workable from a bootable, live CD-ROM. Log files can be stored on a hard disk, and configuration data is stored on a USB mass storage media or a floppy disk and kept on a RAM disk during run-time. Due to its Debian base, a vast manifold of firewalling, routing, and proxy packages is available. It comes with an intuitive, easy to use Web administration interface and support, and is free to use for home users.
GKrellM is a GTK-based stacked monitor program that charts SMP CPUs, disks, load, active net interfaces, and internet connections. There are also builtin monitors for memory and swap, file systems with mount/umount feature, mailbox checking including POP3 and IMAP, clock/calendar, laptop battery, sensors (temperatures, voltages, and fans), and uptime. It has LEDs for the net monitors and an on/off button and online timer for PPP. There is a GUI popup for configuration, plugin extensions can be installed, and many themes are available. It also features a client/server monitoring capability.
The ipaudit package records and displays network activity. It is useful for identifying heavy bandwidth users, intrusive telnet sessions, denial of service attacks, and scans. It includes ipaudit, which stores counts of bytes and packets for every combination of host/port pairs and protocol. The utilities total and ipstrings can be used to investigate network traffic records from the command line. ipaudit-web can collect network traffic statistics and generate Web reports.
The IPchains Firewalling Module, part of the RockSolid Linux Distribution, allows you to easily maintain a firewall based on ipchains with the Webmin look and feel. It has three modes: Newbie (select one of five security levels), Template (define from a table with protocols and directions what should be allowed to pass your firewall), and Expert (have the real ipchains experience by having every parameter under control by editing a script file which has all ipchains rules). Nearly all of the ipchains options are supported.