50 Switching ConfigurationPort SecurityThis section describes the Port Security feature.OverviewPort Security:• Allows for limiting the number of MAC addresses on a given port.• Packets that have a matching MAC address (secure packets) are forwarded; all other packets (unsecurepackets) are restricted.• Enabled on a per port basis.• When locked, only packets with allowable MAC address will be forwarded.• Supports both dynamic and static.• Implement two traffic filtering methods. These methods can be used concurrently.– Dynamic Locking: User specifies the maximum number of MAC addresses that can be learned ona port. The maximum number of MAC addresses is 100. After the limit is reached, additionalMAC addresses are not learned. Only frames with an allowable source MAC address are forwarded.– Static Locking: User manually specifies a list of static MAC addresses for a port.OperationPort Security:• Helps secure network by preventing unknown devices from forwarding packets.• When link goes down, all dynamically locked addresses are ‘freed.’• If a specific MAC address is to be set for a port, set the dynamic entries to 0, then only allow packetswith a MAC address matching the MAC address in the static list.• Dynamically locked MAC addresses are aged out if another packet with that address is not seen withinthe age-out time. The user can set the time-out value.• Dynamically locked MAC addresses are eligible to be learned by another port.• Static MAC addresses are not eligible for aging.
