Port Mirroring

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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, that can be used to diagnose or debug issues on the network.

The E8, E24 and E48 all support port mirroring. Using Datto Networking, you can configure traffic from 1 to 8 ports to be mirrored into a specific port with just a couple clicks and you can have up to 4 such active, concurrent, mirroring sessions on any single switch. Further, Datto offers you the flexibility of choosing whether to mirror just the incoming (Tx), outgoing (Rx) or all traffic from each of the source ports. Lastly, port mirroring can be used in conjunction with Link Aggregation to mirror traffic from an LAG into another port for analysis.

 

Mirroring Ports

To configure port mirroring on a switch, follow these steps:

1. Log into your Partner Portal account and the specific network that is managing your switches

2. Go to the Manage > Switches Page and click on the name of the specific switch you'd like to set up port mirroring on, to bring up its configuration pane.

3. Once in the configuration pane, select the ports you want to mirror (sources and destination) by checking the boxes on the left most column of the specific ports  and clicking on the blue "Mirror" button (example below is setting up a mirror with ports 1, 2, 3 and 4)

4. You can now choose which of the selected ports you want the traffic to be mirrored to by choosing it from the "Destination ID" drop down (in this case, we're selecting port 4 as the mirror destination). Notice that the other ports automatically become sources.

5. You can then choose to specify, port by port, what type of traffic (Tx, Rx or both), to mirror into the destination (in this case, we're mirroring received packets from port 1, transmitted packets from port 2 and all traffic from port 3, into port 4). Note that you can also choose to remove any port from the mirroring session (in case you change you mind) right from this interface itself, by unselecting the check box next to a port number

6. Once you have made your selections, click save and you'll see that the mirroring session has been created and is indicated by a common (red) color coded text in the 'Mirroring' column. You'll also note that the destination port is noted as 'Destination' and the other ports are marked with the port number of the destination port that they are mirroring into followed by the traffic type (Tx-only, Rx-only or Tx+Rx) that is being mirrored.

7. You can continue to set up more mirroring sessions, if you choose to. And each time you add a new session, a different color code is used to group the ports of that mirror session together

 

Unmirroring Ports

To remove one or more ports from a mirroring session, simply click on the port(s) that you want to remove and click 'Unmirror'. You'll notice that the 'Mirror' button itself doubles up as an 'Unmirror' button when the time is right!

 

You can unmirror ports from multiple mirroring sessions at the same time with just one click of the unmirror button! 

Important Notes:

1. If you unmirror the destination port, the entire mirror session is torn down. 

2. If you unmirror any port in a two port mirror, the entire mirror session will be torn down

3. You cannot mirror ports that are also being aggregated (LAG) with each other

4. You can mirror one or more ports of an aggregate into a port that is not part of an aggregate group (LAG)


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