ping is one of the most fundamental network tools. It uses icmp packets to determine the performance of a connection between devices. The primary purpose of ping is to check whether you can reach the remote system and that the remote system can reach you back (if the system is online, if the packet is blocked by a firewall etc.) before we spend time carrying out more detailed scans to discover the running operating system and services.
ping measures the time for IMCP packets to travel between devices (using echo packet from host and echo reply packet from the target device).
We can use ping as ping MACHINE_IP or ping HOSTNAME. In the latter, the system needs to resolve HOSTNAME to an IP address before sending the ping packet.
Opts
-c- number of packets to send-nin Windows
-s- packet size- 56 bytes by default; with 8 bytes from IMCP header it translates to 64 bytes
No ping reply?
There are a few explanations that would explain why we didn’t get a ping reply:
- The destination computer is not responsive
- still booting up or turned off, or the OS has crashed
- It is unplugged from the network
- There is a faulty network device across the path.
- A firewall is configured to block such packets.
- The system is unplugged from the network.