A network engineer configures port security on a Cisco Catalyst switch interface using the command `switchport port-security mac-address sticky`. The switch successfully learns the MAC address of the connected host and dynamically adds it to the running configuration. However, after the switch is rebooted, the port security configuration no longer retains the previously learned host MAC address. Which administrative oversight caused this issue?
- The engineer did not save the running configuration to the startup configuration after the MAC address was learned.Cevap
- BThe engineer omitted an explicit permit statement at the end of the interface port security access list.
- CThe switch port had a native VLAN mismatch configured on the switch-to-switch trunk link.
- DThe engineer configured RADIUS authentication instead of TACACS+ for local MAC address database persistence.
Cevap
The host MAC address was lost because the running configuration containing the learned sticky MAC address was not saved to the startup configuration prior to the switch reboot.
When port security is configured with sticky MAC learning, the switch dynamically converts learned MAC addresses into static-like entries within the running configuration (`running-config`). Because the running configuration resides in volatile RAM, any switch reboot causes these learned entries to be cleared unless an administrator explicitly copies the running configuration to the startup configuration in NVRAM using `copy running-config startup-config` or `write memory`.
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Anahtar Kavram
Port Security Sticky MAC Address Persistence and NVRAM Configuration Management
Tahmini Süre:45s