Goodbye Skype! Dedicated Support Continues via Teams & Slack

Home

Blog

How to Watch TCP and UDP Ports in real-t...

How to Watch TCP and UDP Ports in real-time in a Linux Server

How to Watch TCP and UDP Ports in real-time in a Linux Server

NetShop ISP

NetShop ISP · Blog Author

Jun 17, 2021 · Technical Tutorials

As a web hosting provider we work closely with our customers who, in majority, are system administrators and network engineers. One of the most frequent challenges a Linux server administrator will face, is the monitoring of network connections/sockets on the server to identify and resolve bottlenecks.

In this article we explain, in simple words, what TCP and UDP are and how you can monitor the activity on your Linux server in real-time.

What is TCP and UDP?

The Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP) are both network protocols responsible for data transfers between an end-user’s device to a web server.

For example, when chatting on Skype the TCP and UDP protocols are used so that your messages can travel from your laptop or mobile, through Skype’s Servers, and reach your Skype contact; and vice-versa.

How to List all Open TCP and UDP Ports in Linux

The netstat is system administrators’ favorite command to list all open ports on a Server. However, as it has been deprecated, you can now also use the ss utility for details network statistics.

Simply type the following command:

sudo netstat -tulpn
Using netstat on Linux server to list all Open TCP and UDP Ports

Explanation of the netstat command flags/parameters

-t : Enables listing of TCP ports
-u : Enables listing of UDP ports
-l : Displays only listening sockets
-n : Displays the port number
-p : Displays the process name

How to Watch TCP and UDP Ports in Real-Time

To monitor the TCP and UDP ports on your Linux server in real-time, the following command should be used:

sudo watch netstat -tulpn

or

sudo watch ss -tulpn
Real-time monitoring of TCP and UDP ports on Linux Server

Once you are done with Ports monitoring, you can type Ctrl-C to exit the watch utility.

Free VPS Trial

No Credit Card Required.

Recent Posts

Goodbye Skype! Dedicated Support Continues via Teams & Slack

Goodbye Skype! Dedicated Support Continues via Teams & Slack

15 April, 2025

NetShop ISP Unveils Revamped Website With Modern UI & Improved Navigation

NetShop ISP Unveils Revamped Website With Modern UI & Improved Navigation

09 April, 2025

Cloud Hosting Trends 2025: Bare Metal, Hybrid Cloud & Web3 Hosting

Cloud Hosting Trends 2025: Bare Metal, Hybrid Cloud & Web3 Hosting

24 March, 2025

How To Install Virtualizor KVM on Ubuntu 22.04

How To Install Virtualizor KVM on Ubuntu 22.04

05 March, 2025

NetShop ISP Appoints Yiota Pingou as Chief Technology Officer

NetShop ISP Appoints Yiota Pingou as Chief Technology Officer

18 February, 2025