PING & EXTENDED PING

Ping is used to test network connections. It can be used to determine if a remote device can be reached across the network. Most ping tools use Internet Control Message Protocol (ICMP). They send request messages to a target network address at periodic intervals and measure the time it takes for a response message to arrive. these tools typically support options like

1. How many times to send request?

2. How large of a request message to send?

3. How long to wait for each reply?

4. The output of ping varies depending on the tool. Standard results includes

It is often believed that "Ping" is an abbreviation for Packet Internet Groper. The ICMP ECHO REQUEST and ECHO REPLY messages are sent and received by the ping command. In fact, when people say that they "sent a ping packet", they really mean that they sent an ICMP echo request. The Echo Request simple means that the host to which it is addressed should reply to the packet. the Echo Reply is the ICMP message type that should be used in the reply. The Echo Request includes some data that can be specified by the ping command; whatever data is sent in the Echo Request is sent back in the Echo Reply.

CODES THAT THE PING COMMAND RECEIVES IN RESPONSE TO ITS ICMP ECHO REQUEST::

!   =   ICMP Echo Reply received

.    =   Nothing was received before the ping command timed out

U   =  ICMP unreachable (Destination) received

N   =  ICMP unreachable (Network) received

P   =  ICMP unreachable (Port) received

Q  =  ICMP Source Quench received

M =  ICMP can't Fragment Message Received

?   =  Unknown Packet Received