The Fort Knox firewall from Internet Devices (peddled off a dozen times, now
owned by Alcatel) had this feature -- working.  We later took a unit apart
and found it to be nothing more than a FreeBSD 2.2.8 box on a pentium 233 w/
4 or 5 Intel NICs.  There was an RS232 loopback adapter on the serial port.
Removing it caused the box to halt, with a pc-speaker audioable notification.
It was very useful, as improperly shutting down the unit meant almost certain
improper operation afterwards.


Put it in -- people will use it.

-lava