Resolution
A secure port has a default of one MAC address. The default can be changed to any value between 1 and 3,000. The upper limit of 3,000 guarantees one MAC address per port and an additional 3,000 across all ports in the system.
In Cisco Catalyst 2900XL/3900XL switches, issue the port security [max-mac-count addresses] command to set the maximum number of secure addresses that this port can support. The maximum number of addresses that the port can learn is 132.
In Cisco Catalyst 3750 switches, issue the switchport port-security maximum value command to set the maximum number of secure MAC addresses for the interface. The maximum number of secure MAC addresses that can be configured on a switch stack is determined by the maximum number of available MAC addresses allowed in the system. This number is determined by the active Switch Database Management (SDM) template. Refer to Configuring SDM Templates for more information.
After the maximum number of secure MAC addresses is set on a port, include the secure addresses in an address table in one of these ways:
- Configure the secure MAC addresses with the switchport port-security mac-address mac_address interface configuration command.
- Configure all secure MAC addresses on a range of VLANs with the port-security mac-address VLAN range configuration command for trunk ports.
- Allow the port to dynamically configure secure MAC addresses with the MAC addresses of connected devices.
- Configure some of the addresses and allow the rest to be dynamically configured.
Refer to articleHow to configure port security on Cisco Catalyst switches running CatOS for details about how to configure port security on Cisco Catalyst switches running CatOS.
Refer to articleHow to configure port security on Cisco Catalyst switches that run Cisco IOS system software for details about how to configure port security on Cisco Catalyst switches that run Cisco IOS system software.
