iperf3
What it is
iperf3 is a network measurement tool for assessing achievable bandwidth on IP networks. It measures TCP, UDP, or SCTP throughput using client and server functions, and reports throughput, loss, and other test results. Users can adjust parameters for timing, protocols, and buffers. Results from either side can be emitted as JSON, including line-delimited JSON for real-time parsing, and a library makes its functionality available to other programs. The project is free under a three-clause BSD license. Officially supported platforms listed are Ubuntu Linux, FreeBSD, and macOS; Windows is not officially supported, and the FAQ points Windows users with problems to iperf2. ESnet provides source distributions rather than binary packages and recommends checking their SHA256 checksums. iperf3 originated as the bandwidth tester for perfSONAR, which remains its primary user base. It is not backwards compatible with the original iperf.
For and against
For
- Measures TCP, UDP, and SCTP throughput
- Client and server functions are included
- Test timing, protocol, and buffer settings are adjustable
- JSON output supports real-time parsing
- Free under a three-clause BSD license
Against
- Windows is not officially supported
- ESnet does not distribute binary packages
- Not backwards compatible with the original iperf
- Source distributions require checksum verification
The verdict
iperf3 offers configurable network throughput tests, with client/server operation and machine-readable output. Check its platform support and compatibility limits before choosing it.
Who it suits
iperf3 suits people who need configurable TCP, UDP, or SCTP bandwidth measurements on its officially supported platforms. Its client/server operation and JSON output may also suit workflows that parse or reuse test results.
Plans and prices
iperf3
Three-clause BSD license · source distributions; ESnet does not distribute binary packages
Read 2 Oct 2026 · software.es.net
On the record
- Compatibility limit
- iperf3 is not backwards compatible with the original iperf.software.es.net · read 2 Oct 2026
- Distribution
- ESnet does not distribute binary packages; the project lists third-party packages and provides source distributions.software.es.net · read 2 Oct 2026
- Integrations
- iperf3 was developed initially as the bandwidth tester for the perfSONAR measurement suite, which the project identifies as its primary user base.software.es.net · read 2 Oct 2026
- Integrity
- The project recommends verifying SHA256 checksums for source distributions before use.software.es.net · read 2 Oct 2026
- Latest release
- The project news page lists iperf-3.22 as released on 2026-09-29, with security and minor bug fixes.software.es.net · read 2 Oct 2026
- Library
- iperf3 includes a library version of its functionality that can be used in other programs.software.es.net · read 2 Oct 2026
- License
- iperf3 is released under a three-clause BSD license.software.es.net · read 2 Oct 2026
- Output
- Client or server output can be emitted as JSON, including line-delimited JSON for real-time parsing.software.es.net · read 2 Oct 2026
- Protocols
- It measures TCP, UDP, or SCTP throughput and includes both client and server functionality.software.es.net · read 2 Oct 2026
- Purpose
- iperf3 measures achievable bandwidth on IP networks and reports throughput, loss, and other test results.software.es.net · read 2 Oct 2026
- Security
- The project directs reports of potential security issues to [email protected].software.es.net · read 2 Oct 2026
- Support
- The project provides a developer mailing list and GitHub issue tracker for questions and bug reports.software.es.net · read 2 Oct 2026
- Supported platforms
- Ubuntu Linux, FreeBSD, and macOS are the only officially supported platforms listed by the project.software.es.net · read 2 Oct 2026
- Test options
- Users can tune test parameters related to timing, protocols, and buffers.software.es.net · read 2 Oct 2026
- Windows support
- iperf3 is not officially supported on Windows, and the FAQ recommends iperf2 for Windows users having trouble.software.es.net · read 2 Oct 2026
