Port Mirroring



This article describes how to configure port mirroring on a Datto Managed Switch.


  • Datto Managed Switches


Port Mirroring is used to send copies of packets seen on one or more ports to another port of a switch. It is commonly used by network administrators to easily collect and analyze data on active networks, and then used to diagnose or debug issues.

All E-Series and L-Series switches support port mirroring. You can have up to four active, concurrent mirroring sessions on any single switch, and can be used in conjunction with Link Aggregation to mirror traffic from a LAG into another port for analysis.


1. Navigate to a device web session for your switch.

2. Click the Manage drop-down and choose Switches.

Figure 1: Switches

4. Click your desired switch. Its configuration pane will appear.

3. Select the source and destination ports by checking the boxes on the left most column of the specific ports.

Figure 2: Selecting ports

4. Select which port you want the traffic to be mirrored from by choosing it from the Destination ID drop down. Other ports will automatically become sources.

Figure 3: Destination Port ID.

5. Specify, for each source port, whether it will transmit Tx only, Rx only, or both types of traffic.

Figure 4: Source port IDs & transmission types

6.Click Save Changes. Each port will now be denoted with its destination port, transmission type, or as the destination port under the Mirroring column.

Figure 5: A single port mirroring session

Each port mirroring session will have an additional color scheme attributed to it, as seen in Figure 6.

Figure 6: Multiple port mirroring sessions

Unmirroring Ports

1. Select the checkbox next to a mirror port. You can select multiple ports at a time.

2. Click Unmirror.

Figure 7: Unmirroring ports

 3. Click OK.

Important Notes

  • If you unmirror the destination port, the entire mirror session is torn down. 
  • If you unmirror any port in a two port mirror, the entire mirror session will be torn down.
  • You cannot mirror ports that are also being aggregated with each other.
  • You can mirror one or more ports of an aggregate into a port that is not part of an aggregate group.

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