Cisco Certified Network Professional Practice Test 2025 – Your All-in-One Guide to Exam Success!

The command 'vlan dot1q tag native' specifically addresses how native VLAN traffic is treated on trunk ports. By issuing this command, the Cisco switch is configured to tag packets that are part of the native VLAN with a specific VLAN ID. This is important as it helps prevent double-tagging attacks that can exploit the default behavior of trunking, where packets in the native VLAN are sent untagged.

In a typical VLAN setup, the native VLAN is used for management and untagged traffic, which can create vulnerabilities if malicious users are able to craft packets that can bypass security measures. By tagging the native VLAN packets, the command ensures that these packets are treated consistently like other tagged VLAN traffic, thereby mitigating the risk of attackers exploiting untagged packets to manipulate VLANs or gain unauthorized access.

The other options relate to different functionalities that are not achieved by this specific command. For instance, enabling trunking on the native VLAN, setting the native VLAN to the default, or designating a VLAN for management traffic do not directly involve addressing the security concern of double-tagging in the context of trunked ports.