Ping Command Recognition

Constantly understanding of knowledge...

Ping is the abbreviation of packet Internet grope (Internet package Explorer). It is a command used to check whether the network is smooth or the network connection speed. Return address (127. x. x. x) is the loopback address (loopback address), which is the internal IP address of the Host IP stack. It is mainly used for network software testing and communication between local processes.ProgramOnce data is sent using the return address, the protocol software returns immediately and never transmits data over any network. If Ping passes 127.0.0.1 and the local IP address, the installation and configuration of the local NIC are correct. The following describes the specific workflow of Ping.

The Ping workflow is as follows: if you run ping192.168.0.1 on host a, ping the command to build a fixed format ICMP to send the packet together with the address 192.168.0.1 to the IP layer protocol, the IP layer protocol uses the IP address 192.168.0.1 as the destination address, the local IP address as the source address, and some other control information to construct an IP packet and find a way to obtain the MAC address of 192.168.0.1, to build a data frame at the data link layer. To prevent other computers from using the ping command to test server connectivity, you can disable the ICMP port on the server.

In the past, the ping command only sent and received data packets to check whether the LAN is smooth. Now, we have taken a closer look at it, I will also understand more clearly. This is the process of learning, from being vague to being clear.