Building Debian CD-ROMS Part 1 - dfsbuild
"dfsbuild is a relatively recent tool which allows you to build livecds based upon Debian. It's intended purpose is to allow you to install Debian from scratch, but because it is a simple means of building livecds it is useful for people who use Debian and don't wish to reinstall.
This is the first of two systems we're going to look at for building directly bootable, custom, Debian CD-ROMs the other being bootcd next time. [...]
If you're wondering what you'd use a bootable Debian CD-ROM for then here are a couple of suggestions:
* Use as a rescue disk in case you render your machine unbootable.
* Use to install Debian on a new machine.
* Creating a booting disk which will serve as a webserver, mounting the documents its serving via NFS.
* Acting as a proxy server, or traffic sniffer in a simple manner.
* Testing a potentially compromised machine without disturbing it."