Testing Local Network Speed on Linux, Windows, and macOS with Speedtest-cli & iPerf

Testing Local Network Speed on Linux

Speedtest-cli

Speedtest-cli ( https://github.com/sivel/speedtest-cli) is a command‑line utility that measures download and upload bandwidth by connecting to the nearest Speedtest server.

sudo apt-get install speedtest-cli
speedtest-cli

iperf

iperf ( https://iperf.fr) provides detailed performance metrics such as bandwidth, latency, and packet loss. Install it, start a server, then run a client against the server.

sudo apt-get install iperf
iperf -s
iperf -c <server_ip>

Testing Local Network Speed on Windows

Using the Speedtest App

Open a browser to https://www.speedtest.net, click the “Go” button, and view download, upload, and latency results.

PowerShell basic test

Run the following command to test connectivity, latency, and bandwidth to a target host.

Test-NetConnection -ComputerName example.com -Port 80

iPerf for Windows

Download the Windows binary from https://iperf.fr/iperf-download.php, install it, then start a server and client.

iperf -s
iperf -c <server_ip>

Testing Local Network Speed on macOS

Speedtest by Ookla App

Visit https://www.speedtest.net or download the app from the Mac App Store, then click “Go” to run the test.

Terminal basic test

Download a test file to gauge download speed.

curl -o /dev/null http://speedtest.wdc01.softlayer.com/downloads/test10.zip

Install and run iPerf via Homebrew

Install Homebrew from https://brew.sh, then install iPerf, start the server, and run the client.

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
brew install iperf
iperf -s
iperf -c <server_ip>

Advanced Testing Methods and Additional Tools

Wireshark

Install Wireshark ( https://www.wireshark.org), capture traffic on the appropriate interface, and analyze packets for detailed performance insights.

Ping for latency

ping <target_ip>

iPerf UDP test

Enable UDP testing with the -u flag to evaluate real‑time applications.

iperf -u -c <server_ip>

Network Optimization

Optimize network settings

Adjust MTU size : view current size with ip link show and change it, e.g., sudo ip link set dev eth0 mtu 1500.

Enable Jumbo frames : ensure all network devices support Jumbo frames and configure them where possible.

Use caching and CDN

Local cache : employ a proxy such as Squid on Linux/macOS to reduce external requests.

CDN : deploy static assets to services like Cloudflare, Akamai, or Amazon CloudFront for faster delivery.

Update drivers and firmware

Keep network‑adapter drivers and router/switch firmware up to date to avoid performance regressions.

Monitor network performance

Collect and visualize metrics with Prometheus ( https://prometheus.io) and Grafana ( https://grafana.com) to quickly spot and resolve issues.