Cisco Certified Network Associate (CCNA) Practice Exam

Which router IOS commands can help troubleshoot LAN connectivity problems? (Select three)

1. ping

2. tracert

3. ipconfig

4. show interfaces

The correct answer is: ping

The chosen command, "ping," is a fundamental tool used in troubleshooting LAN connectivity issues. It works by sending Internet Control Message Protocol (ICMP) Echo Requests to a specified IP address and then waiting for a response. If the target device is reachable, it will send back an Echo Reply, thereby confirming that the device is alive and that there is a viable path between the two devices. If no reply is received, it indicates a potential connectivity issue, such as a down interface, network segment failure, or a routing problem. "show interfaces" is another useful command in this context, as it provides detailed information about each interface on a router. It shows the status of the interfaces (up or down), the encapsulation type, errors, and the amount of traffic passing through them. By analyzing this output, network administrators can identify issues such as interface errors or misconfigurations affecting LAN performance. Although "tracert" (or "traceroute" on Cisco devices) is useful for diagnosing paths taken by packets through the network, it primarily serves to identify routing paths rather than local LAN connectivity issues. "ipconfig," while useful for displaying the IP configuration of a Windows device, isn't an IOS command that can be executed on Cisco equipment