Sick et all,
I was thinking more that you'd need to find a way to make the Ethernet
cards burp out packets unintentionally. Has anyone looked into the new
manageable ENet cards? Can they be made to reveal themselves? Your Ethernet
TDR would send some magic packet which made the Ethernet cards reply
unbeknownst to the owner of the card (only if the transmit part of the card
is still enabled though).
TDR does emit a pulse like radar or sonar. It measured impedance changes in
the wire based on reflection (VSWR?). You can even see the changes that
individual connectors make to the general impedance of a cable.
> From: dharris @
> To: firewalls @
COM; Sick Puppy <sikpuppy @
> Subject: Re: Finding a wiretap or NIC card with a TDR
> Date: Tuesday, September 30, 1997 9:12 AM
> Doesn't TDR *require* actively creating a pulse so you can measure its
> reflection? If you don't know when you emitted the pulse how can you
> the time until its echo? I suppose a pattern-matching oscilloscope could
> configured to measure the time between an outgoing 'ping' and its echo
> ______________________________ Reply Separator
> Subject: Finding a wiretap or NIC card with a TDR
> Author: Sick Puppy <sikpuppy @
com> at INTERNET-MAIL
> Date: 9/27/97 9:40 PM
> We have reason to believe that some looser geeks or phederal phucks
> have sneaked a wiretap onto a network segment that we often cross.
> We also happen to have a couple of Time Domain Reflectometers left over
> from previous academic research on satellite channels. If we plug the
> TDR's into the network segment there is a real good chance that the
> looser geeks or whatever will spot us so we need to run in stealth
> The network segment hosts several Unix boxes on which we are privileged
> users. (Our network, our boxes of course. What else could they be?)
> Does anybody know of any software that will run on a Unix or NT box and
> provide the same information as a TDR?
> Does anybody know of an equivalent software package that will run on Unix
> or NT and help us find the wiretap or silent NIC card we think is there?
> Sick Puppy, the Cat_Eating_Dawg