The ping command is detailed

Introduction: We use the ping command every day, but we may not be quite sure how ping works, and it is not clear how many of the details are in the running results. Find out the information, and now share with you how ping works and related details.

How the a.ping command works
The ping command is primarily used to test connectivity between the local host and the remote host. The ping command sends an ICMP response request datagram (Echo request) to the remote host, and the remote host receives a response reply datagram (echo Reply). The landlord's opportunity calculates the time between the return of the response datagram from the sending response request data, which determines whether the local host is properly connected to the remote host, and what the network is like.

The significance of b.ping results
For the results of the ping command , we mainly focus on the return time of the datagram, packet loss rate, from these two factors can also be broadly determined whether the network stability. Of course, the network here includes the local network and the network of routing nodes through which the datagram is routed. For example, the data return time fluctuation is very large, it indicates that the network is unstable. Ping gets the datagram return time between 150 to 350 is normal, basically does not affect the site access speed. and the packet loss rate can directly reflect the local host to the server network connection condition is not very good, specific which node problem, we can again through the TRACERT command to query.

C. How do I calculate the number of routes that the local host has passed to the target host?
By default, the ping command sends 4 request datagrams, each containing 32 bytes of data. If all goes well, you will get 4 responses to the datagram's return. The ping command displays the time in MS, and the TTL is displayed at time to Live. We can calculate how many routers the datagram has passed through the TTL value, calculated as: Source location TTL start value-The TTL value when returned. Source Location The TTL start value is a power that is slightly larger than the return TTL of 2. If the return value is 119, then the TTL starting value is 2 of the 7--128, so the datagram passes from the source location to the destination location through 9 router segments. If the return TTL value is 246, then the starting value of the TTL is 256, so the datagram passes through 10 router segments from the source location to the target location.

D.ping Results Analysis

E.ping attack
It is worth mentioning that, because the ping command can customize the size of the sending datagram and can endlessly tell the send, some people with ulterior motives will use the ping command as a DDoS tool, such as the use of hundreds of Internet-connected computers/ The broiler continuously sends a large number of PING commands to the database and makes some large websites paralyzed (ping attacks).

f.ping Command Common parameter description
-N [Count] determines the number of times a response request is sent. The default value is 4.
The-l size determines the size of the sending request packet. The default is 32 bytes.
-T sends the request packet continuously until it is terminated by pressing CTRL + C.

The ping command is detailed