Port Monitor on Dell PowerConnect switch series

Follow these steps in order to capture traffic on Dell PowerConnect switch series:

SW#configure SW(config)# interface ethernet g23 SW(config-if)# port monitor g21

In the following example I have configured Ethernet port g23 to monitor and capture all traffic which traverses through port g21. In Cisco terminology port g23 is the SPAN port while mirroring the traffic from port g21.

The default behavior is to capture traffic on both directions, rx and tx, but we have the option to choose only one direction:

SW(config-if)#port monitor g21   rx                   Monitor received frames only   tx                   Monitor transmitted frames only    <CR>

If you ever configured some other port before you may encounter a situation where more then one port is sending traffic to the monitor port, in order to validate this use the command:

SW-2# show ports monitor Source Port Destination Port  Type     Status   ----------- ---------------- ------- ----------     g19           g23         RX,TX    active       g21           g23         RX,TX    active

Note that monitor too many ports to a single port may lead to overwhelming of data rate which can lead to packet drop by the monitor port.