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iperf3

software.es.net

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Spec score 8.1 #10 of 33 in Network Testing Software

What it is

iperf3 is a free command-line network measurement tool that reports achievable IP-network bandwidth, throughput, loss, and related results. It includes client and server functions for TCP, UDP, and SCTP tests, with adjustable timing, protocol, and buffer settings. Client or server output can be emitted as JSON, including line-delimited JSON for real-time parsing, and a library version can be embedded in other programs. The project uses a three-clause BSD license and lists Ubuntu Linux, FreeBSD, and macOS as its officially supported platforms. Windows is not officially supported; its FAQ points users with Windows problems toward iperf2. ESnet supplies source distributions rather than binary packages and recommends checking SHA256 checksums. iperf3 began as a perfSONAR bandwidth tester, its primary user base. It is not backwards compatible with the original iperf. Version 3.22 was released September 29, 2026.

Spec sheet

Purpose
iperf3 measures achievable bandwidth on IP networks and reports throughput, loss, and other test results.Read 2 Oct 2026 · software.es.net
Integrations
iperf3 was developed initially as the bandwidth tester for the perfSONAR measurement suite, which the project identifies as its primary user base.Read 2 Oct 2026 · software.es.net
Security
The project directs reports of potential security issues to [email protected].Read 2 Oct 2026 · software.es.net
Support
The project provides a developer mailing list and GitHub issue tracker for questions and bug reports.Read 2 Oct 2026 · software.es.net
License
iperf3 is released under a three-clause BSD license.Read 2 Oct 2026 · software.es.net
Founded
2010Read 28 Sep 2026 · software.es.net
Compatibility limit
iperf3 is not backwards compatible with the original iperf.Read 2 Oct 2026 · software.es.net
Distribution
ESnet does not distribute binary packages; the project lists third-party packages and provides source distributions.Read 2 Oct 2026 · software.es.net
Integrity
The project recommends verifying SHA256 checksums for source distributions before use.Read 2 Oct 2026 · software.es.net
Latest release
The project news page lists iperf-3.22 as released on 2026-09-29, with security and minor bug fixes.Read 2 Oct 2026 · software.es.net
Library
iperf3 includes a library version of its functionality that can be used in other programs.Read 2 Oct 2026 · software.es.net
Output
Client or server output can be emitted as JSON, including line-delimited JSON for real-time parsing.Read 2 Oct 2026 · software.es.net
Protocols
It measures TCP, UDP, or SCTP throughput and includes both client and server functionality.Read 2 Oct 2026 · software.es.net
Supported platforms
Ubuntu Linux, FreeBSD, and macOS are the only officially supported platforms listed by the project.Read 2 Oct 2026 · software.es.net
Test options
Users can tune test parameters related to timing, protocols, and buffers.Read 2 Oct 2026 · software.es.net
Windows support
iperf3 is not officially supported on Windows, and the FAQ recommends iperf2 for Windows users having trouble.Read 2 Oct 2026 · software.es.net

Plans and prices

iperf3 Free Three-clause BSD license · source distributions; ESnet does not distribute binary packages Read 2 Oct 2026 · software.es.net

Every iperf3 plan and price →

Strong points and limits

Strong points

  • Free three-clause BSD license
  • TCP, UDP, and SCTP throughput tests
  • JSON and line-delimited JSON output
  • Adjustable timing and buffer parameters
  • Client, server, and library forms

Limits

  • Windows is not officially supported
  • ESnet does not distribute binary packages
  • Not backwards compatible with original iperf

Who it suits

It suits network engineers and developers measuring TCP, UDP, or SCTP performance, especially perfSONAR users and people who need machine-readable output or a reusable library.

Verdict

iperf3 offers configurable, scriptable bandwidth testing across its listed Unix-like platforms. Windows users and those needing packaged binaries should account for the stated distribution limits.

Where Specifiction places it

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