Linux iperf3 Guide

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.

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Table of Contents

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

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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

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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

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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

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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

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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

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Troubleshooting

Connection Errors

Check network:

# Test connectivity
ping server-ip

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

# Check iperf3 service
systemctl status iperf3

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Summary

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

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Next Steps

• Network Utilities - Network tools
• Networking - Network setup
• iperf3: https://iperf.fr/

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