Easily Monitor and Manage Network Connections with Netstat on Raspberry Pi

Learn how to check port status on your Raspberry Pi using the netstat command, a powerful tool for viewing network connections and their current status. …


Updated October 12, 2023

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Learn how to check port status on your Raspberry Pi using the netstat command, a powerful tool for viewing network connections and their current status.

Raspberry Pi is an affordable mini computer that can be used for various purposes like home automation, media centers, security systems, and more. One of the most important tasks in maintaining your Raspberry Pi system is to keep track of its network connections. Netstat command is a powerful tool available on Raspberry Pi and other Linux-based systems that allows you to view all active network connections and their current status. In this article, we will learn how to use the netstat command on Raspberry Pi to check port status.

Netstat stands for Network Status and it provides information about active TCP/IP connections, including incoming and outgoing connections, ports, protocols, and more. It is an essential tool for network administrators as it allows them to monitor their network traffic and troubleshoot any issues that may arise.

To check port status on Raspberry Pi using netstat command, follow these steps:

  1. Open a terminal window by pressing Ctrl+Alt+T or by going to Menu > Accessories > Terminal.
  2. Type sudo netstat -tulpn and press Enter. This command will display all active network connections along with their PID (process ID), local address, remote address, state of the connection, and the program using that port.

Here is an example output:

Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name    
tcp        0      0 192.168.1.154:8080       0.0.0.0.0:*               LISTEN      -

In this example, we can see that there is a process listening on port 8080 with local address 192.168.1.154. The state of the connection is “LISTEN” which means it is waiting for incoming connections. The PID column shows “-” since the process is not running as root user.

  1. To filter the output and show only specific ports, add -a option followed by the port number you want to check. For example: sudo netstat -tulpn | grep 8080. This will display all connections related to port 8080.
  2. You can also check for specific connection states like “ESTABLISHED” or “CLOSE_WAIT” by adding -s option followed by the state name. For example: sudo netstat -tulpn | grep ESTABLISHED. This will display all established connections on your Raspberry Pi.
  3. To monitor and continuously update the output, use the -w option followed by a number in seconds to specify the refresh interval. For example: sudo netstat -tulpn -w 1. This will refresh the output every second. Press Ctrl+C to stop monitoring.

In conclusion, using the netstat command on Raspberry Pi is an effective way to check port status and monitor network connections. It is a valuable tool for system administrators who need to ensure their Raspberry Pi system is functioning properly and securely. By regularly checking port status and ensuring no unauthorized access or suspicious activities are occurring, you can maintain the integrity of your Raspberry Pi and its connected devices.