Which statement about TTL in a ping reply is correct?

• A. It is a measure of the total bytes transmitted
• B. It indicates the round-trip time to the target
• C. It shows the source port used in the response
• D. It represents the time-to-live field in the IP/ICMP packet, used to limit hops

Answer: (D)

TTL in a ping reply reflects the time-to-live field in the IP header of the ICMP echo reply. This field acts as a hop limit: every router that forwards the packet decrements it by one, and if it reaches zero the packet is dropped. The value you see indicates how many hops remain to reach the destination, not the round-trip time. Initial TTL values vary by operating system (commonly 64, 128, or 255), so the observed TTL is only a rough indicator of distance, not an exact measure. It’s not related to the number of bytes transmitted, the round-trip time, or the source port.