100-140 Question 220
Select 3A user reports that they cannot access a website, and you suspect a network connectivity issue. You decide to use the 'ping' command to troubleshoot. What can the 'ping' command help you determine?
- A
Whether the target host is reachable
- B
The current TCP port status of the target host
- C
The round-trip time (RTT) for packets between your device and the target host
- D
The presence of packet loss in the connection to the target host
- E
The DNS resolution of the target host's IP address
Show answer and explanation
Correct answers: A, C, D
Explanation
The 'ping' command is a basic network troubleshooting tool that sends ICMP Echo Requests to a target host and waits for replies. It can determine reachability, measure round-trip time (RTT), and detect packet loss. However, it is not designed to check TCP port status or directly resolve DNS names to IP addresses.
- A. Correct.
The 'ping' command is primarily used to check if the target host is reachable by sending ICMP Echo Request packets and waiting for a response.
- B. Incorrect.
The 'ping' command does not provide information about the status of TCP ports; for this, tools like 'telnet' or 'netstat' are used.
- C. Correct.
Ping calculates the round-trip time (RTT) for packets to travel to the target and return, providing insights into network latency.
- D. Correct.
The 'ping' command can indicate packet loss by reporting the number of packets sent and received, and any that were lost during transmission.
- E. Incorrect.
The 'ping' command does not resolve DNS directly; it requires you to input either a hostname (which your device resolves to an IP) or an IP address.