Video: The Switch MAC Forwarding Table

[Chris_Skees]

When troubleshooting switch endpoint connectivity, the switch MAC forwarding table is an easy way to find MAC addresses that the switch is currently aware of as well as the port and VLAN numbers for their traffic. Check it out!

This video is part of the Troubleshooting Switch Endpoint Connectivity module in the MS Fundamental Operations course. If you want to learn more, you can complete the module in about 35 minutes or less!

[MatthewG3]

Is there a way to clear the mac table?

[kydave]

Hi, MatthewG3! That's a great question. I don't know of a way to clear the MAC address table from the dashboard. There might be a way via an API call, but will have to research that. Otherwise, the MAC address table is built to learn new entries dynamically, as ethernet frames arrive on switch ports. Existing entries get refreshed the same way. However, learned entries will automatically age out if no further frames are received for a fixed amount of time. That tends to keep the table up-to-date and tidy, with no manual intervention required.

On Catalyst switches, MAC table entries age out after 300 seconds (5 minutes). On MS switches, the age out timer can vary depending on the chipsets used in the specific model.

I hope this helps!