Linux iperf3 Guide - ryzendew/Linux-Tips-and-Tricks GitHub Wiki

Linux iperf3 Guide

Complete beginner-friendly guide to iperf3 on Linux, covering Arch Linux, CachyOS, and other distributions including network performance testing, bandwidth measurement, and network diagnostics.

Table of Contents

  1. iperf3 Installation
  2. iperf3 Basics
  3. Server Mode
  4. Client Mode
  5. Performance Testing
  6. Troubleshooting

iperf3 Installation

Install iperf3

Arch/CachyOS:

# Install iperf3
sudo pacman -S iperf3

Debian/Ubuntu:

sudo apt install iperf3

Fedora:

sudo dnf install iperf3

Verify Installation

Check iperf3:

# Check version
iperf3 --version

# Check help
iperf3 --help

iperf3 Basics

Server Mode

Start server:

# Start server
iperf3 -s

# On specific port
iperf3 -s -p 5201

Client Mode

Connect to server:

# Connect to server
iperf3 -c server-ip

# On specific port
iperf3 -c server-ip -p 5201

Server Mode

Basic Server

Start server:

# Default server
iperf3 -s

# Server on port 5201
iperf3 -s -p 5201

# Server with JSON output
iperf3 -s -J

Server Options

Advanced options:

# Server with interval
iperf3 -s -i 1

# Server with one connection
iperf3 -s -1

Client Mode

Basic Client

Test connection:

# Basic test
iperf3 -c server-ip

# Test duration
iperf3 -c server-ip -t 60

# Test bandwidth
iperf3 -c server-ip -b 100M

Client Options

Advanced options:

# Parallel streams
iperf3 -c server-ip -P 4

# Reverse test (server sends)
iperf3 -c server-ip -R

# UDP test
iperf3 -c server-ip -u

Performance Testing

Bandwidth Test

Measure bandwidth:

# Server
iperf3 -s

# Client (on another machine)
iperf3 -c server-ip -t 60

Throughput Test

Test throughput:

# Multiple streams
iperf3 -c server-ip -P 8

# Bidirectional
iperf3 -c server-ip --bidir

Troubleshooting

Connection Errors

Check network:

# Test connectivity
ping server-ip

# Check firewall
sudo firewall-cmd --list-all

# Check iperf3 service
systemctl status iperf3

Summary

This guide covered iperf3 installation, network testing, and performance measurement for Arch Linux, CachyOS, and other distributions.

Next Steps

This guide covers Arch Linux, CachyOS, and other Linux distributions. For distribution-specific details, refer to your distribution's documentation.