Cisco Catalyst 3550

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Catalyst 3550 Multilayer Switch Command Reference
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Chapter 2 Catalyst 3550 Switch Cisco IOS Commands
switchport port-security
Usage Guidelines A secure port has these limitations:
• A secure port can be an access port or a trunk port; it cannot be a dynamic access port.
• A secure port cannot be a routed port.
• A secure port cannot be a protected port.
• A secure port cannot be a destination port for Switched Port Analyzer (SPAN).
• A secure port cannot belong to a Fast EtherChannel or Gigabit EtherChannel port group.
• When you enable port security on an interface that is also configured with a voice VLAN, set the
maximum allowed secure addresses on the port to two. When the port is connected to a Cisco IP
phone, the Cisco IP phone requires up to two MAC addresses. The Cisco IP phone address is learned
on the voice VLAN, but is not learned on the access VLAN. If you connect a single PC to the Cisco
IP phone, no additional MAC addresses are required. If you connect more than one PC to the Cisco
IP phone, you must configure enough secure addresses to allow one for each PC and one for the
phone.
• Voice VLAN is supported only on access ports and not on trunk ports.
• When you enter a maximum secure address value for an interface, if the new value is greater than
the previous value, the new value overrides the previously configured value. If the new value is less
than the previous value and the number of configured secure addresses on the interface exceeds the
new value, the command is rejected.
• The switch does not support port security aging of sticky secure MAC addresses.
A security violation occurs when the maximum number of secure MAC addresses are in the address table
and a station whose MAC address is not in the address table attempts to access the interface or when a
station whose MAC address is configured as a secure MAC address on another secure port attempts to
access the interface.
When a secure port is in the error-disabled state, you can bring it out of this state by entering the
errdisable recovery cause psecure-violation global configuration command, or you can manually
re-enable it by entering the shutdown and no shut down interface configuration commands.
Setting a maximum number of addresses to one and configuring the MAC address of an attached device
ensures that the device has the full bandwidth of the port.
When you enter a maximum secure address value for an interface, this occurs:
• If the new value is greater than the previous value, the new value overrides the previously
configured value.
• If the new value is less than the previous value and the number of configured secure addresses on
the interface exceeds the new value, the command is rejected.
Sticky secure MAC addresses have these characteristics:
• When you enable sticky learning on an interface by using the switchport port-security
mac-address sticky interface configuration command, the interface converts all the dynamic secure
MAC addresses, including those that were dynamically learned before sticky learning was enabled,
to sticky secure MAC addresses and adds all sticky secure MAC addresses to the running
configuration.
• If you disable sticky learning by using the no switchport port-security mac-address sticky
interface configuration command, the sticky secure MAC addresses are converted to dynamic secure
addresses and are removed from the running configuration. If you remove the sticky MAC addresses
from the running configuration, the sticky secure MAC addresses are removed from the running
configuration and the address table.