Tag Archives: iperf

Iperf Alternatives For Windows

Iperf is the tool to go to when you need an idea of what your network throughput is, the thing is that it requires some use of the command line. Which some people may find challenging, but just because of that doesn’t mean you don’t have other options. From personal experience I know of two applications that mimic Iperf, the difference is that both applications come with a GUI. I am talking about LAN Speed Test and NetStress two applications for Windows design to network throughput measurement.


Not only is NetStress capable of measuring network performance it also has a neat graphical interface, if you are into graphs than consider NetStress. Just like Iperf you need to install NetStress on both the client and server to properly measure two ends of the network.


  • single instance of the application (i.e. each instance can be used as server or server plus client)
  • supports both TCP and UDP data transfers
  • supports multiple data streams
  • variable TCP / UDP segment size
  • rate of packet transmission (Packets Per Second)
  • variable Maximum Transmission Unit (MTU)
  • uplink and downlink modes
  • auto node discovery
  • choice of display units (KBps, Kbps, MBps, Mbps)
  • support for multiple network adapters

Source nutsaboutnets.com

Perhaps the only downside is that unlike Iperf, NetStress is not a portable application. NetStress is available free charge.

Download: NetStress

LAN Speed Test

LAN Speed Test is another options for those of you who need to measure one side of the network, in order to measure you are required to provide access to an existing network file share where LAN Speed Test can write a file to. You can say this application takes a simpler approach to measuring your network.

The application is available in two forms free and paid. Just like Iperf LAN Speed Test is a portable application.

Download: LAN Speed Test

I still prefer Iperf since I’ve been around many IT professionals who swear by it, but in the end its your choice.

Iperf on Windows

Iperf is a neat little tool with the simple goal of helping administrators measure the performance of their network. Worthy of mention is the fact that it can measure both TCP and UDP performance on a network. Iperf is cross platform software and open source.

You can download Iperf.exe from:

Iperf.exe (locally hosted)


Iperf.exe Ucf.edu

Link updated on 12/30/2010

We will be making use of the command line, do not fear the command line Iperf is a simple tool to use.

Say I want to test the available bandwidth between a server(Windows Server 2008) and a client workstation(Windows 7). Iperf will try to move as much data as possible using the available link in order to conduct the test.



Download the Iperf executable and place the file on any directory you wish, my web browser(Firefox) places all downloaded files on the Download directory which is where I will be executing Iperf from.

Note:You will need to open port 5001 on the Iperf server.

Server Setup

Go to Start > All Programs > Accessories > Command Prompt


With the command line prompt open type

cd Dowloads

or the location where the Iperf executable resides.


Now that you are in the same directory as Iperf type

iperf -s

to start the Iperf server. If you look at the screen Iperf listens on port 5001 you may have to open port 5001 on your firewall.


Client Set Up

Imitating the steps above execute Iperf in the same manner, but this time we are going to give the Iperf client different instructions. On the Iperf client command line type

iperf -c

. This will be our client and we are telling Iperf the server is located at


Give Iperf some time to test the connection, after the test is done Iperf will present the results.


The results are easy to understand in this case Iperf managed to transfer 113 Mbytes at 94.5 Mbit/s, the results will changed when used on a busy network which is where Iperf will reveal the amount of available bandwidth in the network.


My previous Iperf on Linux post

Measure network speeds with Iperf

It happens to all of us, sometimes segments of the network may become unusable or slow. The documentation created by the previous administrator may say Gigabit ethernet is supported or enabled across the network, yet only a fraction of the bandwidth is available.

Iperf can measure the throughput of a network, Iperf operates in a client server mode. Best of all it’s open source and cross platform. Iperf is the perfect tool to measure wired and wireless networks, bandwidth is measured through TCP tests.

Iperf installation

For the network test I will install Iperf on two systems, one will act as the server and the other as the client. Iperf is available on the Ubuntu repositories.

sudo apt-get install iperf

Iperf server

Now turn one of the systems in to the Iperf server.

iperf -s

Iperf server output.

Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)

Iperf client

On the Iperf client issue the following command to connect with the Iperf server and initiate the test.

iperf -c

Client side output.

Client connecting to, TCP port 5001
TCP window size: 16.0 KByte (default)
[  3] local port 59291 connected with port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec    113 MBytes  94.5 Mbits/sec

You can see that on this test Iperf successfully transfered 113 MB of data at a network speed of 94.2 Mbits/sec.

You can also tell Iperf to wait before giving you the network results, by adding -t 30 at the end of the command. This will tell Iperf to wait and in the mean time transferer more data across the network.