Posted by: Anonymous Coward
on August 11, 2004 01:16 AM
I can see one use(??) for port knocking, though it's a bit on the dangerous side. You could use it for emergency shutdown in the case that your computer as been compromised and it won't let you in through ssh anymore. The knock sequence would have to be complex enough that the risk of it being triggered by accident is kept at ~0. This suffers from a major security through obscurity problem, though, as intruders would disable the port knocking if this ever became common. (Not that it ever would, of course.)
I actually used something like this on one of my computers a few years ago, but then a single(!) knock was enought to make the computer reboot. I don't recall if I ever had any use for it, and I had to disable it after I told a friend about it. But it was sort of fun, anyway.