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Zorluk: KolayLayer 2 Security Features (Port Security, DHCP Snooping, DAI)

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?

  1. The administrator failed to save the running configuration to the startup configuration after the sticky MAC addresses were learned.Cevap
  2. B
    Sticky MAC addresses are kept only in volatile RAM and are automatically erased upon reboot by default regardless of configuration saves.
  3. C
    The switch port cleared the sticky MAC table because of a native VLAN mismatch detected on the opposing interface.
  4. D
    Port security sticky learning requires PortFast to be configured on the interface to allow permanent MAC storage in NVRAM.

Cevap

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`.

Adım Adım Çözüm

1
Analyze how sticky MAC learning operates in Cisco IOS port security.
When sticky MAC learning is enabled, dynamically learned MAC addresses are immediately placed into the running configuration (`running-config`) as static entries.
This avoids having to manually type static MAC addresses while securing the port.
2
Evaluate the persistence of running configuration entries across switch reboots.
Entries in `running-config` reside in volatile memory and are lost upon a reboot unless explicitly copied to `startup-config`.
To maintain learned sticky MAC addresses permanently across device reloads, the network administrator must execute `copy running-config startup-config` or `write memory`.

Anahtar Kavram

Port Security Sticky MAC Address Persistence
Tahmini Süre:45s
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Konular

Layer 2 Security Features (Port Security, DHCP Snooping, DAI)

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