iperf3 Project News

2017-03-06: iperf-3.1.7 released

SHA256: a4ef73406fe92250602b8da2ae89ec53211f805df97a1d1d629db5a14043734f  iperf-3.1.7.tar.gz

This version of iperf3 contains two documentation fixes, but is otherwise identical to the prior release.

2017-02-02: iperf-3.1.6 released

SHA256: 70f0c72d9e60c6ecb2c478ed17e4fd81d3b827d57896fee43bcd0c53abccb29d  iperf-3.1.6.tar.gz

This version of iperf3 contains two minor fixes. Notably, one of them unbreaks JSON output with UDP tests.

2017-01-12: iperf-3.1.5 released

SHA256: 6e1a6200cd38baeab58ef0d7b8769e7aa6410c3a3168e65ea8277a4de79e5500  iperf-3.1.5.tar.gz

This version of iperf3 makes some improvements to the fair-queue-based pacing and improves the selection of the default UDP packet size. Users who use either of these aspects of iperf3 are encourage to review the release notes for this version.

2016-10-31: iperf-3.1.4 released

SHA256: db61d70ac62003ebe0bf15496bd8c4b3c4b728578a44d0a1a88fcf8afc0e8f76  iperf-3.1.4.tar.gz

This release fixes a few minor bugs, including a (non-security-impacting) buffer overflow fix ported from upstream cjson.

2016-06-08: Security Issue: iperf-3.1.3, iperf-3.0.12 released

SHA256: 60d8db69b1d74a64d78566c2317c373a85fef691b8d277737ee5d29f448595bf  iperf-3.1.3.tar.gz
SHA256: 9393d646e4e616f0cd7864bc8ceacc379f5d36b08003a3d8d65cd7c99d15daec  iperf-3.0.12.tar.gz

These releases address a security issue that could cause a crash of an iperf3 process (it could theoretically lead to a remote code execution). Although the risk for common use cases is believed to be low, all users are encouraged to update to these versions or newer as soon as possible. More information on the security vulnerability can be found in the following ESnet Software Security Advisory:


iperf-3.1.3 also includes support for fair-queueing, per-socket based pacing of tests on platforms that support it (currently recent Linux distributions), as well as several other fixes.

2016-02-01: iperf-3.1.2 released

SHA256: f9dbdb99f869c077d14bc1de78675f5e4b8d1bf78dc92381e96c3eb5b1fd7d86  iperf-3.1.2.tar.gz

This release fixes a couple of minor bugs, including one that results in invalid JSON being emitted for UDP tests.

Older News

2015-11-19: iperf-3.1.1 released

SHA256: 62f7c64eafe19046ba974b3ef2d962a5597194d6fbbddde328a15a5e74110564  iperf-3.1.1.tar.gz

This release fixes a few minor bugs.

2015-10-16: iperf3 Development Status

Beginning with the release of iperf 3.1, ESnet plans to support iperf3 in “maintenance mode”. At this point, we have no definite plans for further iperf3 releases, and ESnet will be providing a very limited amount of resources for support and development, going forward. However, ESnet could issue new iperf3 releases to deal with security issues or high-impact bug fixes.

Requests for support, enhancements, and questions should best be directed to the iperf-dev mailing list. ESnet would be open to adding project members/committers from the community, in case there are developers who are interested in doing more active work with iperf3 and/or supporting the user base.

2015-10-16: iperf-3.1 released

SHA256: 4385a32ece25cb09d4606b4c99316356b3d2cb03b318aa056b99cdb91c5ce656  iperf-3.1.tar.gz

This release adds support for SCTP on supported platforms, better feature detection on FreeBSD, better compatibility with various platforms, and a number of bug fixes.

2015-01-09: iperf-3.0.11 released

SHA256: e01db5be6f47f67c987463095fe4f5b8b9ff891fb92c39104d042ad8fde97f6e  iperf-3.0.11.tar.gz

This maintenance release adds a -1 flag to make the iperf3 execute a single test and exit, needed for an upcoming bwctl release. A few other bugs are also fixed.

2014-12-16: iperf-3.0.10 released

SHA256: a113442967cf0981b0b2d538be7c88903b2fb0f87b0d281384e41b462e33059d  iperf-3.0.10.tar.gz

This maintenance release fixes building on MacOS X Yosemite, as well as making the -w option work correctly with UDP tests.

2014-10-14: iperf-3.0.9 released

SHA256: 40249a2b30d26b937350b969bcb19f88e1beb356f886ed31422b554bac692459  iperf-3.0.9.tar.gz

This maintenance release fixes an issue for a situation in which attempting a UDP test with pathologically large (and illegal) packet sizes could put the iperf3 server in a state where it would stop accepting connections from clients, thus causing the clients to crash when interrupted.

2014-09-30: iperf-3.0.8 released

SHA256: 81b8d91159862896c57f9b90a006e8b5dc22bd94175d97bd0db50b0ae2c1a78e  iperf-3.0.8.tar.gz

This maintenance release is functionally identical to 3.0.7. It incorporates updated license verbage and a minor compilation fix.

2014-08-28: iperf-3.0.7 released

SHA256: 49510e886f9e876cd73dcd80414bfb8c49b147c82125585e09c2a6e92369d3f2  iperf-3.0.7.tar.gz

This maintenance release fixes several minor bugs. Of particular note:

  • A bug that caused some problems with bwctl / perfSONAR has been fixed.
  • A bug that made it possible to disrupt existing, running tests has been fixed.

2014-07-28: iperf-3.0.6 released

SHA256: 3c5909c9b286b6503ffa141a94cfc588915d6e67f2aa732b08df0af73e21938  iperf-3.0.6.tar.gz

This maintenance release includes the following bug fixes:

  • Several problems with the -B option have been fixed. Also, API calls have been added to libiperf to extend this functionality to API clients.
  • Some portability fixes for OpenBSD and Solaris have been merged from the mainline.

As always, more details can be found in the RELEASE_NOTES file in the source distribution.

2014-06-16: Project documentation on GitHub Pages

iperf3 project documentation can now be found at:

This is a GitHub Pages site. In an ongoing series of steps, content will be migrated from the iperf3 wiki to GitHub Pages.

2014-06-16: iperf-3.0.5 released

SHA256: e1e1989985b17a4c03b0fa207004ad164b137e37ab0682fecbf5e93bcaa920a6  iperf-3.0.5.tar.gz

This is the third maintenance release of iperf 3, with few more enhancements and bug fixes. Highlights:

  • A timing issue which caused measurement intervals to be wrong with TCP tests on lossy networks has been fixed.
  • It is now possible to get (most of) the server-side output at the client by using the --get-server-output flag.
  • A number of bugs with --json output have been fixed.

A more extensive list of changes can always be found in the RELEASE_NOTES file in the source distribution.

Note: An iperf-3.0.4 release was planned and tagged, but not officially released.

2014-06-10: New iperf3 download site

iperf3 downloads are now hosted on a new server at ESnet:

Going forward, new releases will be made available in this directory. Older releases will, at least for now, continue to also be available at the previous location.

2014-03-26: iperf-3.0.3 released

SHA256: 79daf3e5e5c933b2fc4843d6d21c98d741fe39b33ac05bd7a11c50d321a2f59d  iperf-3.0.3.tar.gz

This is the second maintenance release of iperf 3.0, containing a few bug fixes and enhancements, notably:

  • The structure of the JSON output is more consistent between the cases of one stream and multiple streams.
  • The example programs once again build correctly.
  • A possible buffer overflow related to error output has been fixed. (This is not believed to be exploitable.)

More information on changes can be found in the RELEASE_NOTES file in the source distribution.

2014-03-10: iperf-3.0.2 released

SHA256: 3c379360bf40e6ac91dfc508cb43fefafb4739c651d9a8d905a30ec99095b282  iperf-3.0.2.tar.gz

Note: Due to a mistake in the release process, the distribution tarball referred to above is actually not compressed, despite its .tar.gz extension. Instead it is an uncompressed tar archive. The file checksum is correct, as are the file contents.

This version is a maintenance release that fixes a number of bugs, many reported by users, adds a few minor enhancements, and tracks the migration of the iperf3 project to GitHub. Of particular interest:

  • Build / runtime fixes for CentOS 5, MacOS 10.9, and FreeBSD.
  • TCP snd_cwnd output on Linux in the default output format.
  • libiperf is now built as both a shared and static library; by default, the iperf3 binary links to the shared library.

More information on changes can be found in the RELEASE_NOTES file in the source distribution.

2014-02-28: iperf migrated to GitHub

The new project page can be found at:


2014-01-10: iperf-3.0.1 released

SHA256: 32b419ef634dd7670328c3cecc158babf7d706bd4b3d248cf95965528a20e614 iperf-3.0.1.tar.gz

During development, there were various distributions of the source code unofficially released carrying a 3.0.0 version number. Because of the possiblity for confusion, this first public release of iperf3 was numbered 3.0.1.