Ping and TCP/IP

Ping is highly used command to see if the machine is responding or not or if the machine is reachable or not. There is one thing which we forget to realize that Ping uses ICMP protocol and does not use any particular port. So Ping tells that machine is reachable and up  but it does not guarantee that machine is reachable on a particular TCP port which many utilities like SFTP , SSH etc. use.  See a nice article at  https://www.rootusers.com/how-to-ping-a-port/


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