The software is available for a variety of operating systems. You can download iPerf binaries from iPerf - The network bandwidth measurement tool for the following operating systems:
You can also download the C++ source code from that page. Alternatively, if you are using a Linux distribution, you may be able to install it using a standard package management tool for the particular distribution of Linux that you are using. E.g., see Installing iperf on CentOS for instructions on how to install the software with yum.
If you install the software on two systems you control, you can test
between those systems. There are also
public iPerf3 servers
in various parts of the world with which you can test. Those systems are
running in server mode, so you use client mode on your local system
when testing with them. You specify client mode with the -c
option. You can see the available options for the program by issuing the
command iperf -h from a
command prompt while in the
directory where you installed the software on the Microsoft Windows system.
C:\>iperf3
Usage: iperf [-s|-c host] [options]
iperf [-h|--help] [-v|--version]
Server or Client:
-p, --port # server port to listen on/connect to
-f, --format [kmgKMG] format to report: Kbits, Mbits, KBytes, MBytes
-i, --interval # seconds between periodic bandwidth reports
-F, --file name xmit/recv the specified file
-B, --bind <host> bind to a specific interface
-V, --verbose more detailed output
-J, --json output in JSON format
--logfile f send output to a log file
-d, --debug emit debugging output
-v, --version show version information and quit
-h, --help show this message and quit
Server specific:
-s, --server run in server mode
-D, --daemon run the server as a daemon
-I, --pidfile file write PID file
-1, --one-off handle one client connection then exit
Client specific:
-c, --client <host> run in client mode, connecting to <host>
-u, --udp use UDP rather than TCP
-b, --bandwidth #[KMG][/#] target bandwidth in bits/sec (0 for unlimited)
(default 1 Mbit/sec for UDP, unlimited for TCP)
(optional slash and packet count for burst mode)
-t, --time # time in seconds to transmit for (default 10 secs)
-n, --bytes #[KMG] number of bytes to transmit (instead of -t)
-k, --blockcount #[KMG] number of blocks (packets) to transmit (instead of -
t or -n)
-l, --len #[KMG] length of buffer to read or write
(default 128 KB for TCP, 8 KB for UDP)
--cport <port> bind to a specific client port (TCP and UDP, default
: ephemeral port)
-P, --parallel # number of parallel client streams to run
-R, --reverse run in reverse mode (server sends, client receives)
-w, --window #[KMG] set window size / socket buffer size
-M, --set-mss # set TCP/SCTP maximum segment size (MTU - 40 bytes)
-N, --no-delay set TCP/SCTP no delay, disabling Nagle's Algorithm
-4, --version4 only use IPv4
-6, --version6 only use IPv6
-S, --tos N set the IP 'type of service'
-Z, --zerocopy use a 'zero copy' method of sending data
-O, --omit N omit the first n seconds
-T, --title str prefix every output line with this string
--get-server-output get results from server
--udp-counters-64bit use 64-bit counters in UDP test packets
[KMG] indicates options that support a K/M/G suffix for kilo-, mega-, or giga-
iperf3 homepage at: http://software.es.net/iperf/
Report bugs to: https://github.com/esnet/iperf
C:\Program Files\iperf>For a Microsoft Windows system, you need only
download the zip file
for Windows, unzip the contents of the file, and then move the two files
within the zip file, which are cygwin1.dll and
iperf3.exe, if you downloaded a version 3 release of the
software, to whatever directory you wish to keep the program in. Note: you
can't test between a host running version 3 and one running version 2; both
systems need to be running a version with the same major version unumber, e.g.,
a 2.x or 3.x version.
The download site offers 32-bit and 64-bit versions of the software. If you have a 32-bit version of Windows, you should use a 32-bit version and if you have a 64-bit version of Windows you should use the 64-bit version. If you don't know whether your version of Microsoft Windows is 32-bit or 64-bit, see Determining if your version of Windows is a 32-bit or 64-bit version.
To test with a public iperf3 server, bouygues.testdebit.info, located in
France, I could issue the command iperf3 -c bouygues.testdebit.info
using the iperf3 software installed on a Microsoft Windows system.
Note: if you see the error message below, you may need to open a command
prompt window in administrator mode to be able to test with iperf on
the Windows system.
C:\Program Files\iperf>iperf3 -c bouygues.testdebit.info Connecting to host bouygues.testdebit.info, port 5201 iperf3: error - unable to create a new stream: Permission denied C:\Program Files\iperf>
To open a command prompt window where you can run the command with administrator permissions, see the instructions at Obtaining a Command Prompt on a Windows 8 System; the steps for other versions of Windows are similar.
If you run the software in client mode, you will see output similar to the following, which is from a test with the public test server bouygues.testdebit.info.
C:\Program Files\iperf>iperf3 -c bouygues.testdebit.info Connecting to host bouygues.testdebit.info, port 5201 [ 4] local 192.168.0.6 port 49894 connected to 89.84.127.53 port 5201 [ ID] Interval Transfer Bandwidth [ 4] 0.00-1.00 sec 512 KBytes 4.19 Mbits/sec [ 4] 1.00-2.00 sec 1.00 MBytes 8.39 Mbits/sec [ 4] 2.00-3.00 sec 896 KBytes 7.35 Mbits/sec [ 4] 3.00-4.00 sec 1.00 MBytes 8.39 Mbits/sec [ 4] 4.00-5.00 sec 896 KBytes 7.34 Mbits/sec [ 4] 5.00-6.00 sec 896 KBytes 7.33 Mbits/sec [ 4] 6.00-7.00 sec 1.00 MBytes 8.39 Mbits/sec [ 4] 7.00-8.00 sec 896 KBytes 7.34 Mbits/sec [ 4] 8.00-9.00 sec 896 KBytes 7.34 Mbits/sec [ 4] 9.00-10.00 sec 1.00 MBytes 8.40 Mbits/sec - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bandwidth [ 4] 0.00-10.00 sec 8.88 MBytes 7.44 Mbits/sec sender [ 4] 0.00-10.00 sec 8.87 MBytes 7.44 Mbits/sec receiver iperf Done. C:\Program Files\iperf>
For this particular test, the client system could achieve a bandwidth of about 7 - 8 Mbs, which was fairly good considering the client system was constrained by a 10 Mbs local area network (LAN) connection.