FirewallBuilder

Several projects came up with a decent distributions intended for a small diskless router/firewall. We have experience with floppyfw and Devil Linux, consequently Firewall Builder has policy install scripts for these. The advantage of using either one of these is that you won't have to install OS and software on the firewall machine; you just pop in a floppy or a CD-ROM and boot from it. This is as close as it comes to the firewall appliance, yet you get a modern Linux kernel and iptables with both. The whole OS is stored on the write-protected media and can be easily replaced or upgraded simply by changing the disk. Floppy FW comes on a single floppy. (These guys managed to pack a kernel, a busybox application and bunch of other programs on a single compressed ram disk.) You don't get ssh with floppyfw though. The firewall configuration is located in a text file that can be edited off-line and then written to the floppy. Firewall Builder's install script also writes the firewall policy to this floppy when you call main menu item Rules/Install. Once configuration is written to the floppy, you insert it in the firewall and reboot. That's it.

Devil Linux comes on a CD-ROM and obviously has lot more stuff on it. They also keep configuration on a floppy disk. Firewall Builder's install script writes firewall policy to this floppy, which you then need to insert in the firewall. See detailed documentation on using Devil Linux on their web site.