System information

Overview 119
18
Port Security
This section describes the Port Security feature.
Overview
Port 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 pack-
ets (unsecure packets) 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 on a port. After the limit is reached, additional MAC 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.
Dynamically locked addresses can be converted to statically locked addresses.
Operation
Port 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 packets with 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 within the 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.
• Dynamically locked addresses can be converted to statically locked addresses.