Installation guide

McAfee® Network Security Platform 6.0 How dongles work
The sole purpose of the dongles is to transpose the transmit signals from pins 4 and 5
(back) to pins 1 and 2 so the Sensor can communicate with standard Ethernet devices
when powered on:
Figure 10: Dongle transposes signals
The inner workings of the dongle are shown in Figure Inner workings of dongle
Figure 11: Inner workings of dongle
When the transmit signals go from the fail closed port on the Sensor to the male end of the
dongle, they do so on pins 4 and 5. When they go from the female end of the dongles to a
standard 10/100 Base-T cable, however, they use pins 1 and 2, which is the Ethernet
standard.
The same approach is used to prevent loops from a Sensor port operating in SPAN mode.
Imagine that ports 2A and 2B are each running in SPAN mode. When the Sensor is
powered on, because each port is configured for SPAN mode, the Sensor software will
prevent traffic from passing between the pair. But when the Sensor is powered off, the
relays will, by design, allow transmit signals to pass over pins 1 and 2. To avoid this
situation, which will only serve to confuse the remote devices (and even possibly create
bridging loops), Sensor ports configured for SPAN mode also transmit on pins 4 and 5 and
therefore require the dongles.
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