What Ping can tell you
- Ping places a unique sequence number on each packet it transmits, and reports which sequence numbers it receives back. Thus, you can determine if packets have been dropped, duplicated, or reordered.
- Ping checksums each packet it exchanges. You can detect some forms of damaged packets.
- Ping places a timestamp in each packet, which is echoed back and can easily be used to compute how long each packet exchange took - the Round Trip Time (RTT).
- Ping reports other ICMP messages that might otherwise get buried in the system software. It reports, for example, if a router is declaring the target host unreachable.