Ping measures the round-trip time for messages sent from the originating host to a destination computer that are echoed back to the source.

The name comes from active sonar terminology that sends a pulse of sound and listens for the echo to detect objects under water.

Options may include the size of the payload, count of tests, limits for the number of network hops (TTL) that probes traverse, interval between the requests and time to wait for a response.

Many systems provide a companion utility ping6, for testing on Internet Protocol version 6 (IPv6) networks, which implement ICMPv6.

In cases of no response from the target host, most implementations display either nothing or periodically print notifications about timing out.

The Echo Reply is returned as: The payload of the packet is generally filled with ASCII characters, as the output of the tcpdump utility shows in the last 32 bytes of the following example (after the eight-byte ICMP header starting with 0x0800): The payload may include a timestamp indicating the time of transmission and a sequence number, which are not found in this example.

The host does not need to wake up all devices completely and may return to low-power mode after a short delay.

Such configuration may be used to avoid a host to enter in hibernation state, with much longer wake-up delay, after some time passed in low power active mode.

[citation needed] A packet including IP and ICMP headers must not be greater than the maximum transmission unit of the network, or risk being fragmented.