Mirroring

How to monitor network traffic through Cisco RSPAN capable switches

Configure Catalyst IOS Switch

  1. Open a session on the switch

  2. Enter configure mode configure terminal

  3. Set the destination RSPAN VLAN

Note:

This should be an unused VLAN.
  vlan <RSPAN VLAN HERE>
  remote-span
  end

For this example, we will use VLAN 400

Example:

vlan 400
remote-span
end
  1. Configure the source port to mirror data from

    monitor session 1 source interface <source interface>
    monitor session 1 source vlan <source VLAN>
    

Example:

monitor session 1 source interface gigabitethernet5/1
monitor session 1 source vlan 1
monitor session 1 source vlan 100
  1. Configure the destination port to send the data to

Example:

monitor session 1 destination remote vlan 400
end
  1. Exit back to configuration mode.

    exit

Once you have verified that your configuration is correct, make sure to save it.