What is the command to view ports in Linux?

Linux command to view ports: 1. lsof command, syntax "lsof -i:port number", can check port occupancy; 2. "netstat -tunlp" command, can display tcp, udp ports and Process and other related situations, the syntax is "netstat -nltp | grep port number".

The operating environment of this tutorial: linux7.3 system, DELL G3 computer.

Linux command to view ports:

The first: lsof command

lsof(list open files) is a Lists the tools used to open files on the current system.

lsof can check the port occupancy

lsof -i:端口号

Example: Check the occupancy of the server 8000 port:

Second ：netstat -tunlp command

netstat -tunlp is used to display tcp, udp ports and processes and other related conditions.

netstat -nltp | grep 端口号

• -t (tcp) Show only tcp related options

• -u (udp) Show only udp related options

• -n Refuse to display aliases and convert all numbers that can be displayed into numbers

• -l Only list the service status in Listen(listening)

• -p Display the name of the program that establishes the relevant link

For example, to view the situation of port 8000, use the following command:

Several states of TCP connection

ESTABLISHED Established

CLOSED Closed

LISTENING Listening

FIN-WAIT-2 Wait for the connection to be closed

TIME-WAIT Wait for enough time to ensure that the server closes the connection normally

Related learning recommendations: linux video tutorial

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