Wikipedia
Devil-Linux
Devil-Linux is a Linux distribution for use as a router/ firewall which boots and runs completely from CD-ROM, DVD or USB flash drive, after booting it can load the system into RAM. Devil-Linux is capable of running on an older PC.
Devil-Linux does not provide a graphical interface, making it a very light-weight distribution. Nevertheless, it includes a wide range of services (e.g. DNS, Web, FTP, SMTP, ...), tools ( MySQL, Lynx, Wget, Samba, ...) and security utilities ( OpenVPN, Shorewall, ...) ensuring a high level of flexibility. Saving the configuration to a USB flash drive or (later write protected) floppy disk, the settings can be restored at boot.
It uses the grsecurity kernel-patch.