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🧪 iPerf3 Network Speed Testing Guide

iPerf is an open-source network performance measurement tool developed by the Internet Performance Working Group. It allows users to test network throughput by creating TCP or UDP streams and sending traffic from one host (client) to another (server). The results show the maximum achievable bandwidth, helping diagnose network issues or validate performance.



🧩 TCP vs. UDP – What’s the Difference?


Protocol

Connection Type

Reliable?

Use Case

TCP

Connection-based

✅ Yes

File transfers, web browsing

UDP

Connectionless

❌ No

Streaming, VoIP, gaming


  • TCP uses a three-way handshake to ensure reliable delivery.
  • UDP sends data without establishing a connection, making it faster but less reliable.



🖥️ Installing iPerf3


Linux (Debian-based systems)


  1. Log in to your Debian-based system.
  2. Run:


   sudo apt-get install iperf3
  1. Press Y when prompted to confirm installation.



Windows


  1. Download iPerf3: https://files.budman.pw/
  2. Extract the zip file to a known location, e.g., Desktop.




▶️ Running iPerf3


Step 1: Start iPerf3 Server on Debian


On the Debian machine:


iperf3 -s


This starts the server in listening mode, waiting for a client connection.




Step 2: Run iPerf3 Client on Windows


  1. Open Command Prompt.
  2. Navigate to the extracted iPerf3 directory:


   cd C:\Users\YourUsername\Desktop\iperf3



  1. Run the client test:


   iperf3.exe -c



To run a reverse test (measuring download on client):


iperf3.exe -c -R



📊 Interpreting the Results


Sample Output


If you're testing from a remote client, the output will show:


  • Sender (Client): Measures upload from client to server.
  • Receiver (Server): Measures download from client to server.


You can swap directions using the -R flag on the client to test the opposite path.




🎥 Video Tutorial



Updated on: 24/12/2025

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