A network administrator enables port security on a switch access port using the command switchport port-security mac-address sticky. Devices connect to the port, and their MAC addresses are dynamically added to the switch configuration. However, after a planned reload of the switch, the port loses all learned MAC addresses and fails to forward traffic for previously connected hosts. What is the primary cause of this issue?
- The administrator failed to save the running configuration to the startup configuration after the sticky MAC addresses were learned.Answer
- BSticky MAC addresses are kept only in volatile RAM and are automatically erased upon reboot by default regardless of configuration saves.
- CThe switch port cleared the sticky MAC table because of a native VLAN mismatch detected on the opposing interface.
- DPort security sticky learning requires PortFast to be configured on the interface to allow permanent MAC storage in NVRAM.
Answer
The administrator failed to save the running configuration to the startup configuration after the sticky MAC addresses were learned.
When `switchport port-security mac-address sticky` is configured, dynamically learned MAC addresses are converted into static-like entries in the active `running-config`. Because `running-config` resides in volatile RAM, these learned MAC address lines are lost during a reboot unless saved to NVRAM (`startup-config`) using `copy running-config startup-config`.
Step-by-Step Solution
Key Concept
Port Security Sticky MAC Address Persistence
Estimated Time:45s