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Netstat command in Linux

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The netstat command is like a special tool in Linux that helps you understand and check things about how your computer connects to the internet. It can tell you about the connections your computer is making, the paths it uses to send information, and even some technical details like how many packets of data are being sent or received. In simple terms, it’s like a window that shows you what’s happening with your computer and the internet. This article will help you learn how to use netstat, exploring different ways to get specific information and giving you a better idea of what’s going on behind the scenes.

Overview of Netstat Command in Linux

`netstat` stands for network statistics. It allows users to display network-related information and diagnose various networking issues. The command has several options that can be combined to retrieve specific details.

Basic Syntax of `netstat`Command in Linux

Below is the general syntax of the netstat command:

netstat [options]

Let’s explore some of the most commonly used options along with examples:

Some Practical Examples of netstat Commands in Linux:

1) Show Both Listening and Non-listening Sockets Using netstat Command in Linux

-a -all : Show both listening and non-listening sockets. With the –interfaces option, show interfaces that are not up.

netstat -a | more 




2) List All TCP Ports Using netstat Command in Linux

This command specifically lists all TCP ports, giving you information about the TCP connections your system is engaged in.

netstat -at



3) List All UDP Ports Using netstat Command in Linux

Similar to the previous example, this command focuses on UDP ports, revealing details about UDP connections.

netstat -au




4) List Only Listening Ports Using netstat Command in Linux

By using this option, you can see only the ports that are actively listening for incoming connections

netstat -l



To list only the listening ports.

5) List Only Listening TCP Ports Using netstat Command in Linux

Narrowing it down further, this command specifically lists the TCP ports that are in a listening state.

netstat -lt




To list only the listening tcp ports.

6) List Only Listening UDP Ports Using netstat Command in Linux

Similarly, this command focuses on displaying only the UDP ports that are actively listening.

netstat -lu




To list only the listening udp ports.

7) List Only Listening UNIX Ports Using netstat Command in Linux

For those working with UNIX systems, this option shows only the UNIX ports that are in a listening state.

netstat -lx




To list only the listening UNIX ports.

8) List Statistics for All Ports Using netstat Command in Linux

This command provides statistical information for all ports, offering insights into network activity.

netstat -s 




To list the statistics for all ports.

9) List Statistics for TCP Ports Using netstat Command in Linux

For a more specific breakdown, this command displays statistics exclusively for TCP ports.

netstat -st




To list the statistics for TCP ports.

10) List Statistics for UDP Ports Using netstat Command in Linux

Similarly, this command focuses on the statistical information related to UDP ports.

netstat -su




List the statistics for UDP ports.

11) Display PID and Program Names Using netstat Command in Linux

This option enriches the output by displaying Process ID (PID) and program names associated with network connections.

netstat -pt




To display the PID and program names.

12) Print Netstat Information Continuously Using netstat Command in Linux

Executing this command continuously prints netstat information, updating at regular intervals to provide real-time insights.

netstat -c




To print the netstat information continuously.

13) Get Non-supportive Address Families Using netstat Command in Linux

To identify non-supportive address families on the system, use this command for a detailed overview.

netstat --verbose




To get the non-supportive address families in the system.

At the end, we have something like this.

14) Get Kernel Routing Information Using netstat Command in Linux

This command retrieves kernel routing information, displaying destination addresses, gateways, and interface details.

netstat -r




To get the kernel routing information.

15) Get Port on Which a Program is Running Using netstat Command in Linux

To find the port on which a specific program, in this case, SSH, is running, use this command.

netstat -ap | grep ssh




To get the port on which a program is running.

16) Identify Process Using a Particular Port Using netstat Command in Linux

This command helps identify the process associated with a given port, such as port 80 in this example.

netstat -an | grep ':80'




To get the process which is using the given port.

17) Get List of Network Interfaces Using netstat Command in Linux

Use this command to obtain a list of network interfaces, providing details about each interface’s activities.

netstat -i




To get the list of network interfaces.

Display Extended Information on Interfaces Using netstat Command in Linux

For extended information on interfaces, similar to the output of the ifconfig command, use this option to gain comprehensive insights.

netstat -ie




To display extended information on the interfaces

Frequently Asked Questions

What is the netstat command in Linux used for?

The netstat command in Linux is a powerful networking tool used to display a variety of information related to network connections, routing tables, interface statistics, and more. It helps users diagnose network issues and gain insights into the current state of network activities on a system.

How do I view all active connections using netstat?

To view all active connections using netstat, you can use the following command:

netstat -a

This command displays both listening and non-listening sockets, providing a comprehensive list of active network connections.

Can netstat show the processes associated with network connections?

Yes, netstat can show the processes associated with network connections. By using the `-p` option, you can include the Process ID (PID) and program names in the output. For example:

netstat -p

This command will display the processes along with their PIDs that are using network resources.

How do I monitor network activity in real-time with netstat?

To monitor network activity in real-time using netstat, you can use the `-c` option. This option continuously updates the netstat information at regular intervals.

For example:

netstat -c

Executing this command will provide ongoing updates on network statistics.

What is the difference between netstat and ss command in Linux?

The netstat and ss commands in Linux both provide information about network connections, but they differ in terms of features and efficiency. ss is considered a more modern and efficient replacement for netstat. It provides faster output, supports more filters, and is generally recommended for users who want a more streamlined and up-to-date tool for viewing network statistics. However, netstat remains widely used and available on many systems.

How to show listening network ports with netstat in Linux?

To display listening network ports using netstat in Linux, you can use the following command:

netstat -tuln

Here’s what each option means:

  • -t: Show TCP connections.
  • -u: Show UDP connections.
  • -l: Display only listening sockets.
  • -n: Show numerical addresses instead of resolving them to hostnames.

This command will provide a list of all listening TCP and UDP ports along with their respective numerical addresses

How to display all network connections with netstat in Linux?

To show all network connections using netstat in Linux, you can use the following command:

netstat -a

Here’s the breakdown of the options:

  • -a: Display all sockets, including listening and non-listening sockets.

This command will show a comprehensive list of all established connections, listening sockets, and other network-related information. Additionally, you can use the -n option to display numerical addresses instead of resolving them to hostnames:

netstat -an

These commands will help you monitor and analyze network connections on your Linux system.

Conclusion

In this article we discussed the netstat command in Linux which is like a special tool that helps you see how your computer connects to the internet. It’s like a window showing you information about connections, data paths, and technical details. This article covers practical examples of netstat commands, from displaying active connections to listing specific types of ports and getting detailed statistics. Whether you’re a beginner or more advanced, netstat offers versatile options. Common questions are answered, making it clear what netstat does and how it differs from other commands like ss in Linux. This knowledge helps users diagnose network issues and understand their system’s internet activities better.



Last Updated : 01 Feb, 2024
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