Cisco Certified Network Associate (CCNA) Practice Exam

Which command identifies the state of the interface and checks for errors?

1. #show interface summary

2. #show interface INTERFACE NUMBER

3. #show ip protocols

4. #show vlan brief

The correct answer is: #show interface INTERFACE NUMBER

The command that reveals the state of the interface and checks for errors is indeed the one that displays detailed information about a specific interface, including its operational status and any errors that may have occurred. By using this command, you can see whether the interface is up or down, the type of encapsulation used, the bandwidth allocated, as well as detailed statistics, including input and output packet errors, collisions, and other interface-specific metrics. The other options serve different purposes; for example, one might provide a summary of multiple interfaces but would not offer the detailed statistics needed to assess individual interface health and error conditions. Another option may include information about routing protocols or VLAN configurations, which are important for network management but irrelevant when focusing specifically on a single interface’s status and performance metrics. Each of these commands is useful in its own context, but the command that focuses deeply on an interface's condition and errors stands out as the most appropriate in this situation.