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Developer(s) The Iperf team
Stable release 1.7.0 / March 13, 2003 (2003-03-13)
Development status stalled
Written in C
Operating system Cross-platform
Type Bandwidth management
License BSD license
Website http://dast.nlanr.net/Projects/Iperf/
Stable release 2.0.8 / April 25, 2015 (2015-04-25)
Development status Only fixes
Written in C
Operating system Cross-platform
License BSD license
Website http://sourceforge.net/projects/iperf2
Stable release 3.1.2 / February 1, 2016 (2016-02-01)
Development status Active
Written in C
Operating system Cross-platform
License BSD license
Website http://software.es.net/iperf

Iperf is a commonly used network testing tool that can create Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) data streams and measure the throughput of a network that is carrying them. Iperf is a tool for network performance measurement written in C. It is a compatible reimplementation of the ttcp program that was developed at the National Center for Supercomputing Applications at the University of Illinois by the Distributed Applications Support Team (DAST) of the National Laboratory for Applied Network Research (NLANR), which was shut down on December 31, 2006, due to termination of funding by the United States' National Science Foundation.

Iperf allows the user to set various parameters that can be used for testing a network, or alternatively for optimizing or tuning a network. Iperf has a client and server functionality, and can measure the throughput between the two ends, either unidirectionally or bi-directionally. It is open-source software and runs on various platforms including Linux, Unix and Windows (either natively or inside Cygwin[1]).

  • UDP: When used for testing UDP capacity, Iperf allows the user to specify the datagram size and provides results for the datagram throughput and the packet loss.
  • TCP: When used for testing TCP capacity, Iperf measures the throughput of the payload. Iperf uses 1024 × 1024 for megabytes and 1000 × 1000 for megabits.

Typical Iperf output contains a time-stamped report of the amount of data transferred and the throughput measured.

Iperf is significant as it is a cross-platform tool that can be run over any network and output standardized performance measurements. Thus it can be used for comparison of both wired and wireless networking equipment and technologies. Since it is also open source, the measurement methodology can be scrutinized by the user as well.

Graphical user interface[edit]

There is a graphical user interface (GUI) front end available called jperf.[2] While there is work on a GUI, the command shell remains the preferred method of use. [3]


A rewrite of iperf from scratch, with the goal of a smaller, simpler code base and a library version of the functionality that can be used in other programs, called iperf3, was started in 2009. The first iperf3 release was made in January 2014. The website states: "iperf3 is not backwards compatible with iperf2.x".

See also[edit]

Public test servers[edit]


External links[edit]