To enable port mirror/monitoring on the Dell PowerConnect 5548 series switches, please follow the following steps:

1. SSH or Telnet to the switch
2. Login to the switch
3. Execute the command: enable
4. Execute the command: config
5. Execute the command: interface gigabitethernet 1/0/##
   1. In this case, use the port number of the device that will be getting the traffic to analyze.  This is the interface your "wireshark" machine would be connected to, to do a packet capture.
6. Execute the command: port monitor gigabitethernet 1/0/##
   1. In this case, use the port number of the device you want to see the network traffic/activity on.  For example, if my device that I wanted to monitor was on gigabit port 1/0/5, I would use that, not the machine that is going to receive the traffic (not your "wireshark" machine).

Once you are done with the forward, you can disable port monitoring/mirror by executing the following command after running through steps 1-5 again: no port monitor gigabitethernet 1/0/##

Last, if you want to see the status of your mirrored/monitored port, you can do so by executing the following command after repeating steps 1-3: show ports monitor