Dynamic ARP Inspection (DAI) is a security feature that validates ARP packets on untrusted interfaces by comparing the MAC address to IP address bindings in the DHCP snooping database or an ARP access-list. If the ARP packet contains invalid or spoofed information, it is dropped and logged. DAI also inspects ARP packets on trusted interfaces, but it does not drop them if they are invalid. Instead, it forwards them to the destination without validation. This allows the switch to support devices that use static IP addresses or have legitimate reasons to send ARP packets with different MAC address to IP address bindings. However, this also means that if a spoofed ARP packet is received on a trusted interface, it will bypass the DAI validation and be forwarded to the destination. This could allow an attacker to poison the ARP cache of other devices and perform a man-in-the-middle attack. Therefore, the correct answer is option B. The switch drops the packet after validation by using the IP & MAC Binding Table. References:
* Understanding and Configuring Dynamic ARP Inspection
* DAI (Dynamic ARP Inspection)
* Dynamic ARP Inspection (DAI) Explanation & Configuration
* Implementing and Operating Cisco Security Core Technologies (SCOR) v1.0