Chapter 8
| General Security Measures
Port Security
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Port Security
These commands can be used to enable port security on a port.
When MAC address learning is disabled on an interface, only incoming traffic with
source addresses already stored in the dynamic or static address table for this port
will be authorized to access the network.
When using port security, the switch stops learning new MAC addresses on the
specified port when it has reached a configured maximum number. Only incoming
traffic with source addresses already stored in the dynamic or static address table
for this port will be authorized to access the network. The port will drop any
incoming frames with a source MAC address that is unknown or has been
previously learned from another port. If a device with an unauthorized MAC
address attempts to use the switch port, the intrusion will be detected and the
switch can automatically take action by disabling the port and sending a trap
message.
mac-learning This command enables MAC address learning on the selected interface. Use the no
form to disable MAC address learning.
Syntax
[no] mac-learning
Default Setting
Enabled
Command Mode
Interface Configuration (Ethernet or Port Channel)
Command Usage
â—† The no mac-learning command immediately stops the switch from learning
new MAC addresses on the specified port or trunk. Incoming traffic with source
addresses not stored in the static address table, will be flooded. However, if a
security function such as 802.1X or DHCP snooping is enabled and mac-
learning is disabled, then only incoming traffic with source addresses stored in
Table 49: Port Security Commands
Command Function Mode
mac-address-table static Maps a static address to a port in a VLAN GC
mac-learning Enables MAC address learning on the selected physical
interface or VLAN
IC
port security Configures a secure port IC
show mac-address-table Displays entries in the bridge-forwarding database PE
show port security Displays port security status and secure address count
PE
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