Re: Network cables as security devices

[borkin () netquest com ((NetQuest) Borkin, Michael)]

Bruce,

  Tip and Ring are electricians terms that have to do with the wiring of
the
pairs, and do not represent transmit and receive   Therefore, the reason
this
didn't work for you is that you cut one wire from both the transmit and
receive
pair.  In an RJ-45 cable the pair on wires 1 & 2 (traditionally the
green
pair)  is the transmit pair and the pair on wires 3 & 6 (traditionally
the
orange pair) are the recieve pair.  To accomplish what you wanted to do
you
must cut wires 1 & 2, not 1 & 3.

  I have no idea if this will actually work the way you wanted, but it
is the
reason it didn't work for you on your first try. Obviously cutting the
transmit
wires means no confirmation packets sent back to the source, and I don't
know
what the overall effect of that would be (my ignorance beginning to
show),
other than no automatic replacement of lost packets.

Hope this helps you straighten this out,

Mike Borkin



  Additional useless information on cabling:

  The pair on wires 4 & 5 (generally blue) are for the main phone line
and the
pair on 7 & 8 (generally brown) are for a secondary phone line.
Ethernet cards
generally ignore these pairs because of this, but this allows for one
Cat 5
cable to carry two telephone lines as well as ethernet traffic.

  In order to quickly connect two computers you can make a crossover
cable by
switching the transmit (1 & 2) and recieve (3 & 6) pairs on one end of
the
cable so that the transmit pair on one end becomes the recieve pair on
the
other and visa-versa.  Having a cable like this is a great tool for
diagnosing
whether something is physically wrong with an ethernet card or with the
actual
network.