Cisco Certified Network Associate (CCNA) Practice Exam

Which command is used to confirm the encapsulation method and authentication type on interfaces?

1. show run

2. show interfaces

3. show ip interface

4. show version

The correct answer is: show interfaces

The command used to confirm the encapsulation method and authentication type on interfaces is "show ip interface." This command provides detailed information about the IP configuration of each interface, including its encapsulation method, which specifies how data frames are wrapped for transmission over a network, and the authentication settings that are in place for that particular interface. By issuing this command, network engineers can effectively diagnose and verify critical configuration parameters that impact interface performance and security. The output will display a range of information pertinent to the status of the interfaces, such as whether they are up or down, IP address assignments, the encapsulation type in use (like Ethernet, Frame Relay, etc.), and any associated authentication settings. The other commands listed serve different purposes. For instance, "show run" reveals the current running configuration of the router or switch but does not specifically highlight encapsulation methods per interface. "Show interfaces" can provide some interface statistics and settings but lacks the detailed protocol-specific information essential for encapsulation and authentication. "Show version" mostly displays hardware and software version details and system uptime, so it does not provide information about interface configurations.