iPerf3 is the industry-standard tool for measuring maximum network bandwidth between two nodes. Unlike online speed tests, it eliminates browser overhead and measures local or wide-area network throughput directly via the command line. It works on a client-server model: one machine listens for traffic, while the other sends data packets to calculate your precise throughput capacity. Step 1: Install iPerf3
You can download binaries directly from the official iPerf Download Page. Install it using your operating system’s package manager: Ubuntu/Debian: sudo apt install iperf3 macOS: brew install iperf3
Windows: Download the .zip file from the iPerf Site, extract it, and open Command Prompt within that folder. Step 2: Set Up the Server
To run a test, you need two machines on the same network. Pick the destination machine to act as the server.
Find the server’s local IP address (e.g., using ipconfig on Windows or ip a on Linux). Run this command to start the server: iperf3 -s Use code with caution.
The server will start listening for traffic on the default port 5201. Ensure your local firewall does not block this port. Step 3: Run the Client Test
Go to your second machine (the client) and target the server’s IP address. Execute the following command: iperf3 -c [SERVER_IP_ADDRESS] Use code with caution.
The client will send TCP traffic to the server for a default duration of 10 seconds. Step 4: Interpret the Results
Once the test finishes, both screens will display a breakdown of the transfer. Look for the final summary line:
[ ID] Interval Transfer Bitrate [ 5] 0.00-10.00 sec 1.10 GBytes 943 Mbits/sec receiver Use code with caution.
Transfer: Total volume of data successfully transmitted during the window.
Bitrate (Bandwidth): Your actual network throughput speed. For example, a healthy Gigabit Ethernet connection typically yields around 940 Mbps after accounting for network overhead. Advanced Testing Commands
Once you master the basic test, use these advanced flags to simulate real-world conditions or stress-test your hardware: 1. Test Bidirectional Throughput
By default, iPerf3 only pushes data from the client to the server. To check your download and upload speeds simultaneously, add the reverse flag: iperf3 -c [SERVER_IP_ADDRESS] -R Use code with caution. 2. Run Parallel Streams
A single TCP connection might not saturate high-bandwidth links due to protocol limitations. Use the -P flag to send multiple data streams at once:
PowerEdge: How to test network bandwidth using ‘iperf’ – Dell
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