Ping is a important computer network administration utility; this tool is used to test whether a particular host is reachable across an Internet Protocol (IP) network and it measure the round-trip time for packets sent from the local host to a destination computer [including the local host's own interfaces]. When using this utility from pan-internet.com your "localhost" become our web server; this feature (changing the IP for where you send the ping) is very helpfully when you need to see from where is coming the reply of a computer. An example in this way is pinging a domain what has been changed the name server - untill replication is done requests to this domain will reply from diferent servers (old server or new server).
How ping operates. It happens by sending Internet Control Message Protocol (ICMP) echo request packets to the target host and waits for an ICMP response (casually called a pong). The ping process measures the round-trip time and records any packet loss. Usually results of the test are printed in form of a statistical summary of the response packets received, including the minimum, maximum, and the mean round-trip times; sometimes there is included and the standard deviation of the mean.
The use of the ping utility is usually described as pinging a host computer but there are various command line options [diferent on each operating system] that enable special operational modes, such as to specify the packet size used as the probe, automatic repeated operation for sending a specified count of probes, time stamping options, or to perform a Flood pinging attention with this, it may be considered as a simple form of denial-of-service attack (you overwhelm the destination/victim with ICMP echo request packets).
Ping-Pong command history. The 1st ping tool was wroted by Mike Muuss in December 1983; it was used to troubleshoot problems in an Internet Protocol network. The name of that program was inspired by the pulses of sound made by a sonar [the operation is analogous to a sonar in submarines]. A big step was done in 2003 when a number of Internet service providers began filtering out ICMP Type 8 (ICMP Echo Request) messages at their network boundaries, considering this as unusefull as a result of the increasing use of ping for target reconnaissance -a example of abusing of ping is some worms such as Welchia that flood the Internet with ping requests in order to locate new computers to infect. The abuse of ping command affects the networks, not only did the availability of ping responses; it added to the overall load on networks and this cause problems for routers across the Internet. Although RFC 1122 prescribes that any host must accept an echo-request and issue an echo-reply in return but hosts that no longer follow this standard are frequent on the public Internet.
ICMP packet
Internet Control Message Protocol packet for ping consist of header (yellow) that contains the protocol and type service, the payload (blue - contains the type of ICMP message, code, checksum, Quenc - here the ICMP echo message, data - a arbitrary length packet). ***ICMP, including ping resides on network layer (the same level as IP - level 3) - that means that ping doesn't use a port for communication.
Ping command is used and in other domains like gaming where the game test the network by sending some ping command and give to the player some informations regarding the experience of gaming what comes.
The term of ping is used to test a feature avaibility. Ussualy this are diferent by the original ping command but the functionality is similar (the sonar): using ping to test if a service is avaible by sending a query to it - requesting a web page to see if the web server is avible, executing a simple sql query to see if the database serve is working properly, or asking information from diferent instant messaging systems to see if a person is conected