ICMP -- Internet Control Message Protocol

Ping is a tool that sends a small piece of data to a different computer. The other computer responds as quickly as it can, and the time between the sending and receiving of the ping is called the ping time. Ping can be used to determine if a remote computer is there, and at the same time, determine the quality of the connection between the 2 computers.

You can use the Ping tool on your Windows 95/NT computer. It is a very simple command, the syntax is ping <hostname>. Let's say you wanted to ping ftp server, ftp.cdrom.com

You should get a screen displaying the output of ping. It will look something like this:

Pinging wcarchive.cdrom.com [] with 32 bytes of data:
Reply from bytes=32 time=352ms TTL=251
Reply from bytes=32 time=304ms TTL=251
Reply from bytes=32 time=267ms TTL=251
Reply from bytes=32 time=282ms TTL=251

The command will ping the specified computer 4 times, by default.

ftp.cdrom.com is also known as wcarchive.cdrom.com. The [] next to it is the computer's IP address. Every computer on the internet has it's own IP address. The size of the data that ping sends is 32 bytes.

As you can see, ftp.cdrom.com replied to those pings. A ping time of 200 - 350 ms is a normal ping time for a 28.8 ppp dialup.

Some errors you may encounter running ping:

Bad IP address badaddress.com
This means you either entered in the wrong hostname, or the hostname does not exist.
Request timed out.
This is a bad message. This means the computer you ping'd did not send back a reply, or it took too long to send back its reply.

Documentation de référence

Documentation obsoletes

Christophe Merlet
©Tous droits réservés
20 décembre 1999