Describes how to use the netstat command!

Describes how to use the netstat command!
From: http://publish.it168.com/2008/0407/20080407001301.shtml

Netstat is used to display statistics related to IP, TCP, UDP, and ICMP protocols. It is generally used to check the network connection of each port on the local machine.

If the data packets received by our computer sometimes lead to data deletion or failure errors, we do not need to be surprised that TCP/IP can allow these types of errors and automatically resend the data packets. However, if the cumulative number of errors accounts for a considerable percentage of the received IP data packets, or the number of errors increases rapidly, then we should use netstat to check the cause.

1. Some common netstat options

Netstat-S

This option displays statistical data for each protocol. If our applicationProgram(For example, a Web browser) is running slowly, or cannot display data such as web pages, so we can use this option to view the information displayed. We need to carefully check the rows of statistics, find the keyword of the error, and then determine the problem.

Netstat-e

This option is used to display statistics about Ethernet. It lists items including the total number of bytes, number of errors, number of delimiters, number of datagram, and number of broadcasts. These statistics include both the number of sent and received data packets. This option can be used to calculate some basic network traffic ).

Netstat-R

This option displays information about the route table, similar to the information shown later when you use the route print command. In addition to valid routes, valid connections are also displayed.

Netstat-

This option displays a list of all valid connection information, including the established connections (established) and those that listen to the listening requests.

Netstat-n

All established valid connections are displayed.

2. The use of netstat

People who frequently access the Internet usually use ICQ. I wonder if we have been harassed by some annoying people. If we want to complain, we don't know how to get started? In fact, as long as we know the IP address of the other party, we can complain to its ISP. But how can I know the IP address of the other Party through ICQ? If the recipient chooses not to display the IP address when setting ICQ, we cannot see it in the Information bar. In fact, we only need to use netstat to easily achieve this: when he is connected to us through ICQ or other tools (for example, we send him an ICQ message or a message ), enter netstat-N or netstat-A at the DOS command prompt to view the IP address or ISP domain name used by the other party to access the Internet, and even the port used is completely exposed.