Ping is a network diagnostic tool that’s used to check if a host in a
network is "alive and responding". Ping uses ICMP messages. More
particularly ICMP query messages.
**So what happens when we ping a machine?
**So what happens when we ping a machine?
-The source sends an ICMP echo-request message to the destination.
-The ping program sets an sequence identifier which gets incremented with each echo-request message. It also sets a TTL (Time-to-live) period.
-Ping also inserts the sending time in the data section of the message.
-If the host is alive and responding, it sends an ICMP echo-reply message back to the source.
-Ping notes the time of the arrival of the response message, uses the sending time in the message part and calculates the Round-trip time.
-It then increments the sequence identifier (as said above) and sends a new echo-request message. This goes on for the number of ping requests set by the user or the program is terminated.
-The ping program sets an sequence identifier which gets incremented with each echo-request message. It also sets a TTL (Time-to-live) period.
-Ping also inserts the sending time in the data section of the message.
-If the host is alive and responding, it sends an ICMP echo-reply message back to the source.
-Ping notes the time of the arrival of the response message, uses the sending time in the message part and calculates the Round-trip time.
-It then increments the sequence identifier (as said above) and sends a new echo-request message. This goes on for the number of ping requests set by the user or the program is terminated.
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