실무에서 자주쓰는 Network 명령어 (Ping, Tracert, Nslookup, Netstat..)

1. Ping

The Ping utility tests connectivity between two hosts.
Ping uses a special protocol called the Internet Control Message Protocol (ICMP).

Also a great way to verify whether you have TCP/IP installed and your Network Card is working.

Even though Server/Computer is on, we can find easily that ping doesn’t work.
Because Server/Computer can block the ping from outside to prevent from DDOS attack. (Block ICMP Protocol)
Also, ICMP Protocol is belonged to OSI Layer 3. so Ping cannot check a port alive

In case of that you want to check any service (port), you can use Telnet or Tcping

Reference : https://www.pluralsight.com/blog/it-ops/top-7-tcpip-utilities-every-networking-pro-should-know , https://ojava.tistory.com/126