How to Test Your Local Internet Speed

I have a local server running Debian, but I found out that the cable connection speed was slow when transferring files from one PC to another through Samba. Using iperf3, I discovered the maximum speed was 85mbps, so the router/AP/modem was capped at the cable.

How to use iperf3?

Download iperf3 on both your server and client (doesn't matter which one is which):

• iperf3 -s # On the server
• iperf3 -c [server IP] # On the client

Installation

On most Linux distributions, you can install iperf3 using your package manager:

• Ubuntu/Debian: sudo apt install iperf3
• CentOS/RHEL: sudo yum install iperf3
• macOS: brew install iperf3

Understanding the Results

iperf3 will show you:

• Transfer rate in Mbits/sec
• Total data transferred
• Test duration
• Retry count (if any packets were lost)

What to Do with Your Results

I tested with both WiFi and cable connections and got different speeds. This helped me identify that the bottleneck was in my cable infrastructure, not the wireless setup.

Use these results to identify network bottlenecks and optimize your local network performance.

TODO: Add screenshot of actual iperf3 output for reference