The firewalk

At least I've seen it mentioned in a utility suite for Linux Security Suite:
Named Trinux quite old though look here:

http://linuxtoday.com/news_story.php3?ltsn=1998-12-17-013-10-NW-SW
But I'll seen it before I am sure of that.

Here comes to other maybe clarifieng answers:
Look here both are an explanation actually:

http://packetstorm.securify.com/assess.html

http://www.ussrback.com/UNIX/unixscanners.htm
But I am sure I've seen a long one somewhere.
I will point to it when I remember where I
saw it.
Meanwhile maybe it will shred a little
light over the word :-)