Comprehensive Explanation: An ACL (Access Control List) is used to define rules for permitting or denying packets based on criteria such as IP addresses, protocols, or ports. However, the ACL only takes effect when it is applied to a service module, such as an interface or a firewall rule. This ensures that traffic is filtered according to the ACL rules as it passes through the device. Without being applied, the ACL rules are inactive and do not influence traffic.

Detailed Explanation:The 802.11ax standard, also known as Wi-Fi 6, supports theoretical speeds over 5 Gbit
/s and is designed for high-efficiency wireless networking in dense environments. (Reference: HCIA-WLAN Training Material, IEEE 802.11 Standards)

Comprehensive Explanation: To prevent unauthorized changes to the router's configuration, the administrator can take several steps. Configuring an ACL to restrict management access ensures that only authorized users, such as the administrator, can log in to the router. Additionally, using AAA (Authentication, Authorization, and Accounting) allows the administrator to manage user permissions and control access to the router's functions based on user roles. Port-security is used for limiting MAC addresses on switch ports, and login privilege levels should be set appropriately but not limited to level 0, which restricts almost all actions.