100-150 Question 221
Select 3A user reports that they cannot access a web application hosted on a server. As a support technician, you run the 'ping' command to test connectivity to the server, and it fails. What would be the most logical next diagnostic command(s) to run to investigate the issue further?
- A
traceroute (or tracert) to the server's IP address
- B
nslookup or dig for the server's domain name
- C
show ip route on the user's device
- D
netstat on the server
- E
arp -a on the user's device
Show answer and explanation
Correct answers: A, B, E
Explanation
When troubleshooting connectivity issues after a failed ping, it is important to investigate the path to the destination using traceroute, verify DNS resolution using nslookup or dig, and review the ARP table to check for local connectivity issues. These steps help isolate the cause of the issue, whether it is related to the network path, DNS, or local device configuration.
- A. Correct.
traceroute (or tracert) helps identify where the connection is failing by mapping the route to the server. This is a logical next step after a failed ping.
- B. Correct.
nslookup or dig checks if the server's domain name is resolving correctly to its IP address. If there is a DNS issue, the user will not be able to reach the server.
- C. Incorrect.
show ip route is used to verify routing on network devices, not on end-user devices. This option is not applicable in this scenario.
- D. Incorrect.
netstat on the server checks for open ports and active connections, but this is not the next logical step when diagnosing from the user's perspective.
- E. Correct.
arp -a displays the ARP table on the user's device, which can help verify if the user's device has an ARP entry for the server's IP address. This can be useful in diagnosing connectivity issues.