How to monitor network traffic through Cisco Catalyst switches

Configure Catalyst Switch

  1. Open a session on the switch
  2. Enter configure mode
    configure terminal
  3. Check what existing monitor sessions exist
    show monitor session
  4. Set the interface to monitor
    monitor session <session number> source interface <interface>
    monitor session 1 source interface gigabitethernet0/0/1
  5. Configure the destination port to send the data to
    monitor session <session number> destination interface <interface> encapsulation replicate
    monitor session 1 destination interface gigabitethernet0/0/2 encapsulation replicate
  6. Exit back to configuration mode

Ensure you save your configuration once you have verified it is configured correctly