Static mac address configuration cisco

You cannot enable persistent MAC learning on an interface on which no-mac-learning is enabled.

Understanding and Using Persistent MAC Learning

If you move a device within your network that has a persistent MAC address entry on the switch, use the clear ethernet-switching table command to clear the persistent MAC address entry from the interface. If you move the device and do not clear the persistent MAC address from the original port it was learned on, then the new port will not learn the MAC address of the device and the device will not be able to connect.

If the original port is down when you move the device, then the new port will learn the MAC address and the device can connect.

However, if you do not clear the persistent MAC address on the original port, then when the port restarts, the system reinstalls the persistent MAC address in the forwarding table for that port. If this occurs, the persistent MAC address is removed from the new port and the device loses connectivity.

After you set a new MAC limit for the interface, the system clears existing entries in the MAC address forwarding table associated with the interface. You can enable it to allow dynamically learned MAC addresses to be retained on an interface across restarts of the switch.

Cisco layer 2 switching and Port Security

Help prevent traffic losses for trusted workstations and servers because the interface does not have to relearn the addresses from ingress traffic after a restart. Protect the switch against security attacks—use persistent MAC learning in combination with MAC limiting to protect against attacks while still avoiding the need to statically configure MAC addresses.

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When the initial learning of MAC addresses up to the number specified by the MAC limit is done, new addresses will not be allowed even after a reboot. The port is secured because after the limit has been reached, additional devices cannot connect to the interface. The first devices that send traffic after you connect are learned during the initial connection period.

You can monitor the MAC addresses and provide the same level of security as if you statically configured each MAC address on each interface, except with less manual effort.

Solved: Mac address dynamic and static - Cisco Community

Persistent MAC learning also helps prevent traffic loss for trusted workstations and servers because the interface does not have to relearn the addresses from ingress traffic. Persistent MAC learning allows retention of dynamically learned MAC addresses on an interface across restarts of the switch or if the interface goes down.


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Display the MAC addresses that have been learned. Related Topics.

Cisco Nexus 5000 Series NX-OS Software Configuration Guide

A layer 3 switch that has all ports configured in one VLAN also works without issues. If the layer 3 switch has ports configured for different VLANs you must change the configuration to enable the switch to operate correctly with a FireCluster. For general information, see:. This example does not include all the other steps to configure a FireCluster.

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WatchGuard provides interoperability instructions to help our customers configure WatchGuard products to work with products created by other organizations. If you need more information or technical support about how to configure a non-WatchGuard product, see the documentation and support resources for that product.

In this example, the FireCluster configuration has one external and one internal interface.