🧪 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

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)

Log in to your Debian-based system.
Run:
sudo apt-get install iperf3
Press Y when prompted to confirm installation.

Windows

Download iPerf3: https://files.budman.pw/
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

Open Command Prompt.
Navigate to the extracted iPerf3 directory:
cd C:\Users\YourUsername\Desktop\iperf3

Run the client test:
iperf3.exe -c <Server_IP>

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

iperf3.exe -c <Server_IP> -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.

Results Interpretation (Server on left, client on right)

🎥 Video Tutorial