Here's a 3-step instruction on how to configure SPAN for Cisco Catalyst 1900 Series Switch
Step 1: Log on to the web manager for your switch.

Step 2: Click on the "SPAN" link at the top of the web page, and showthe "SPAN Configuration" page.

Step 3: Select a monitoring port and add all the ports to be monitored. In this case, we set the port "Ethernet8" as monitoring port and the computer running sniffers can connect to it.
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