A one-way data cable is designed to receive information but not transmit it. This makes for an undetectable but direct way to monitor traffic. Now let’s have a practise on it:

1. What we need:

  •  A length of Cat5 cable
  • Two RJ-45 connectors
  • Soldering Gun
  • Crimp tool

2. Wire the end of the cable that you will plug into the sniffer as a normal patch cable using pins 1, 2, 3, and 6.

3. Modify the end that will be plugged into the switch by removing an inch or so of wire 1 and wire 2.

4. Strip both ends of the removed wires.

5. Solder wire 1 to wire 3 and wire 2 to wire 6 so that the transmit and receive wires are looped. These wires should then be carefully placed in an RJ-45 connecter and crimped.


The connection is illustrated below: