Packet Internet Groper (Ping) Utility

Packet Internet Groper (Ping) Utility

The Ping utility is used to determine whether the local host computer is capable of exchanging datagrams with another host. Ping will continue to operate when there are problems with the Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) or higher level applications. If Ping succeeds it confirms that the Network adapter, cabling and routers are in order.

Ping sends datagrams to a host specified by its Internet Protocol (IP) address, or its Fully Qualified Domain Name (FQDN) using the Internet Control Message Protocol (ICMP) echo request command. If the specified host is present it replies with the ICMP echo reply.

Ping displays statistics including the number of lost datagrams and the response time in milliseconds.

Ping sends four ICMP echo requests consisting of 32 bytes of data (the alphabet plus a, b, c, d, e and f). Four replies indicate a working system.

Ping displays the Time To Live (TTL) value from which you can guess the number of routers used in transit. The initial TTL value will be a power of 2 (2, 4, 8, 16, 32, 64, 128,etc), therefore if the returned TTL is 59, 5 routers utilised would be a good guess.

Examples

Pinging 127.0.0.1 with 32 bytes of data:

Reply from 127.0.0.1: bytes=32 time<10ms TTL=128

Ping statistics for 127.0.0.1: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 0ms, Average = 0ms

Pinging martin-s [127.0.0.1] with 32 bytes of data:

Reply from 127.0.0.1: bytes=32 time<10ms TTL=128

Ping statistics for 127.0.0.1:

Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 0ms, Average = 0ms

Pinging 169.254.248.209 with 32 bytes of data:

Reply from 169.254.248.209: bytes=32 time<10ms TTL=128

Ping statistics for 169.254.248.209: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 0ms, Average = 0ms

Pinging 62.136.48.88 with 32 bytes of data:

Reply from 62.136.48.88: bytes=32 time<10ms TTL=128

Ping statistics for 62.136.48.88: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 0ms, Average = 0ms

Pinging a FQDN instead of an IP address tests the computers ability to resolve an IP address from a Domain Name. If this fails but pinging the IP address succeeds, it suggests a problem with the Domain Name System (DNS) or Hosts file.

Ping 127.0.01 or Ping localhost is directed at the local IP software and does not leave the computer. Failure indicates problems with the software installation.

Pinging the IP address of the local host should always succeed. If it works with the network cable disconnected it may be caused by another host on the network with the same IP address.

A successful ping of the default gateway indicates that this router is working.

Usage: ping [-t] [-a] [-n count] [-l size] [-f] [-i TTL] [-v TOS] [-r count] [-s count] [[-j host-list] | [-k host-list]] [-w timeout] destination-list

Options: -t Ping the specified host until stopped. To see statistics and continue - type Control-Break; To stop - type Control-C.

-a Resolve addresses to hostnames.

-n count Number of echo requests to send.

-l size Send buffer size.

-f Set Don't Fragment flag in packet.

-i TTL Time To Live.

-v TOS Type Of Service.

-r count Record route for count hops.

-s count Timestamp for count hops.

-j host-list Loose source route along host-list.

-k host-list Strict source route along host-list.

-w timeout Timeout in milliseconds to wait for each reply.