Port occupancy query guide in Linux environment

Port occupancy query guide in Linux environment

In the Linux operating system, port occupancy is an important information that we often need to know. Understanding which ports in the system are occupied by which processes can help us troubleshoot network problems, optimize system resource utilization, and protect system security. This article will introduce several common methods for querying port occupancy in a Linux environment, and attach specific code examples.

1. Use the netstat command to query port occupancy

netstat is a network tool that can be used to view information such as network connections, routing tables, and network interfaces of the system. Through the netstat command, we can quickly query the occupancy of each port in the system.

The specific command format is as follows:

netstat -tuln

Among them, the option -t indicates to display the information related to the TCP protocol, -u indicates to display the information related to the UDP protocol, and -l indicates to display the port in the listening status. , -n means to display the port number in numerical form.

Example:

$ netstat -tuln

After executing the above command, the system will list the TCP and UDP ports in the current listening status and the corresponding process information.

2. Use the lsof command to query port occupancy

lsof is a powerful tool that can display open files, network connections and corresponding process information in the system. Through the lsof command, we can query the port information being used in the system.

The specific command format is as follows:

lsof -i:端口号

Example:

$ lsof -i:80

After executing the above command, the system will list the process information occupying port number 80.

3. Use the ss command to query port occupancy

The ss command is a powerful tool used to display statistical information about network sockets. Use the ss command to query the port occupancy in the system more quickly.

The specific command format is as follows:

ss -tuln

Among them, the option -t indicates to display the information related to the TCP protocol, -u indicates to display the information related to the UDP protocol, and -l indicates to display the port in the listening status. , -n means to display the port number in numerical form.

Example:

$ ss -tuln

After executing the above command, the system will list the TCP and UDP ports in the current listening status and the corresponding process information.

To sum up, through the three commands netstat, lsof and ss, we can easily and quickly query the port occupancy status in the Linux system. These methods can help us promptly discover and deal with problems caused by port occupation and ensure the normal operation and security of the system. Hope the above content is helpful to you.

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