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Configuring Port Security
Use the Security > Port Security page to configure the maximum number of device
MAC addresses that can be learned by a switch port, stored in the address table,
and authorized to access the network.
When port security is enabled on a port, 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 address
table will be authorized to access the network through that 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.
Command Usage
◆
The default maximum number of MAC addresses allowed on a secure port is
zero (that is, disabled). To use port security, you must configure the maximum
number of addresses allowed on a port.
◆
To configure the maximum number of address entries which can be learned on
a port, specify the maximum number of dynamic addresses allowed. The switch
will learn up to the maximum number of allowed address pairs <source MAC
address, VLAN> for frames received on the port. When the port has reached the
maximum number of MAC addresses, the port will stop learning new
addresses. The MAC addresses already in the address table will be retained and
will not be aged out.
Note that you can manually add additional secure addresses to a port using the
Static Address Table
◆
When the port security state is changed from enabled to disabled, all
dynamically learned entries are cleared from the address table.
◆
If port security is enabled, and the maximum number of allowed addresses are
set to a non-zero value, any device not in the address table that attempts to use
the port will be prevented from accessing the switch.
◆
If a port is disabled (shut down) due to a security violation, it must be manually
re-enabled from the Interface > Port > General page
◆
A secure port has the following restrictions:
It cannot be used as a member of a static or dynamic trunk.
■
It should not be connected to a network interconnection device.
■
Parameters
These parameters are displayed:
◆
Port – Port identifier.
(page
169).
– 317 –
Chapter 12
| Security Measures
Configuring Port Security
(page
94).
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