iperf.scottlinux.com – Public iperf Server [Update: iperf3 only]

By | 2013/07/17

I created a public iperf server to test your internet connection (iperf3 only). Here are the details!

Nov 2014 Edit: I have had to change this server to be iperf3 only. Sorry!

The server is located at:


Ok now what?
1. iperf3 is required for this server.

Fedora and CentOS EPEL users can install iperf3 with:

$ sudo yum install iperf3

Older versions of Ubuntu and Debian:

For now, must build iperf3 from source from https://github.com/esnet/iperf .

Users of Debian Jessie, iperf3 is available!

2. Once iperf3 is installed, run:

$ iperf3 -c iperf.scottlinux.com

This will test the outgoing bandwidth of your internet connection as one possible test.

Here is an example output:

$ iperf3 -c iperf.scottlinux.com
Connecting to host iperf.scottlinux.com, port 5201
[  4] local 2001:470:e4a9:1:3e97:eff:fe69:137e port 37003 connected to 2600:3c01::f03c:91ff:fe6e:5a91 port 5201
[ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
[  4]   0.00-1.00   sec   565 KBytes  4.63 Mbits/sec    0   50.7 KBytes       
[  4]   1.00-2.00   sec   764 KBytes  6.26 Mbits/sec    0   92.0 KBytes       
[  4]   2.00-3.00   sec  1.43 MBytes  12.0 Mbits/sec    0    171 KBytes       
[  4]   3.00-4.00   sec  3.42 MBytes  28.7 Mbits/sec    0    340 KBytes       
[  4]   4.00-5.00   sec  3.23 MBytes  27.1 Mbits/sec   47    265 KBytes       
[  4]   5.00-6.00   sec  3.36 MBytes  28.2 Mbits/sec    0    300 KBytes       
[  4]   6.00-7.00   sec  3.36 MBytes  28.2 Mbits/sec    0    322 KBytes       
[  4]   7.00-8.00   sec  2.80 MBytes  23.5 Mbits/sec   29    166 KBytes       
[  4]   8.00-9.00   sec  2.24 MBytes  18.8 Mbits/sec    0    183 KBytes       
[  4]   9.00-10.00  sec  1.68 MBytes  14.1 Mbits/sec    0    191 KBytes       
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-10.00  sec  22.8 MBytes  19.1 Mbits/sec   76             sender
[  4]   0.00-10.00  sec  21.9 MBytes  18.4 Mbits/sec                  receiver

iperf Done.


36 thoughts on “iperf.scottlinux.com – Public iperf Server [Update: iperf3 only]

  1. Ryan Milton

    This is great! I tried to install iperf to run as a server on FreeBSD with
    make install clean -C /usr/ports/benchmarks/iperf,

    and it seems to have installed, but when I run the command

    server02# iperf -s -p 999

    I get: iperf: command not found. Why would that be?

    1. Scott Miller Post author

      It sounds like iperf is not in your path,

  2. John Doe

    Thanks for providing open iperf Server and Merry Christmas.

  3. Christian

    Thanks a lot for the server!! You made my day!!! 🙂

  4. Kiril Bugajev

    That’s great. This is exactly what I was looking for.

  5. Troy Carpenter

    Thanks for the server. This has helped me to get Charter see there was a problem with my upstream speeds (supposed to get 4Mbps, get 0.4Mpbs most of the time). I needed a linux based speed test tool, and found iperf. Of course then I needed a public iperf server and found this one!

  6. Setterlee

    Great work dude!!!

    This iperf server help me a lot because I don’t trust on speedtest.net.

    BTW, do you know how get more bits rate on a wifi? I have a netgear wnr2000v3 with dd-wrt and the max bits rate is 20mbps even if i put the clients side by side with the router 🙁

    1. Scott Miller Post author

      To get 802.11n speeds in wifi, make sure all devices connecting to it are N (only) and make sure the wifi is set to broadcast on 802.11n only.

  7. AJ

    Thanks a TON Scott !
    Very useful and handy – can easily & quickly troubleshoot various issues on your Internet.

  8. Alex

    Could you explain how you set up the iperf server? I’d be interested on making my own.

    1. Scott Miller Post author

      Thanks! I will soon write up some info. In short, I wrote a few init scripts to have iperf run as a service. One service for TCP, another service for UDP.

      1. JP Papillon

        Would you mind sharing your init scripts?
        (in particular for Debian systems).

        1. Scott Miller Post author

          Here is a paste with three init scripts. One for iperf v2 TCP, one for iperf v2 UDP, and one for iperf3.


          Note that this is obsolete by systemd. I will make a future scottlinux post about setting up a service with systemd which is much easier than init scripts.

          1. JP Papillon

            I was troubled why you mentioned 2 scripts. After switching to iperf3, only one is needed, as I understand.

            I really hope that systemd will simplify init script. I wonder if it will add another slice of cruft or distribution maintainers will have the time / know-how to rebuild these scripts from foundation.

  9. David Vannucci

    Just used your server, thank you for providing this.

  10. Markus

    Hi Scott,

    I have used your Iperf3 server some days ago. The problem is that the connection terminates after 150-180 seconds.

    1. Scott Miller Post author

      Thank you. Try again perhaps? I have recently updated to the latest iperf3 version.

  11. Chris

    Client connecting to iperf.scottlinux.com, TCP port 5001
    TCP window size: 16.0 KByte (default)
    [ 3] local port 55539 connected with port 5001
    [ ID] Interval Transfer Bandwidth
    [ 3] 0.0-10.0 sec 768 MBytes 643 Mbits/sec

  12. sernan

    thanks for setting this up , very helpful indeed in troubleshooting! Kudos to you Scott!

  13. ccc

    Thanks for the public server.

    I would like to monitor my download speed. I think this is not possible with public servers.

    Trying with

    iperf -c iperf.scottlinux.com -d

    doesn’t work for me. I’ve opened the 5001 port in my linux machine (i’m using a VirualBox linux) but it doesn’t work.


    1. Scott Miller Post author

      Use iperf3 to run in reverse mode (tack R) to do a download test.

       $ iperf3 -R -c iperf.scottlinux.com


      1. Alex

        I’m not sure if -R is a reverse test as you said. It’s not listed with iperf -h. Instead iperf -d would be a dual test so you would be uploading and downloading simultaneously.

  14. ccc

    i’ve notice the same problem using jperf in windows directly in the host


  15. Doug Kenline

    I have been trying for the last few days and it seems to be down. I click on Run IPerf! and I get no green lines coming accross the chart.

    After awhile it says connect failed.

    Am I doing something wrong or has something changed? It had been working great for me before this.

    bin/iperf.exe -c iperf.scottlinux.com -P 1 -i 1 -p 5001 -f k -t 10
    connect failed: Connection timed out.

    I’ve tried different machines and different internet connections but can’t get it to work again now.

    Any suggestions or insight on this?

    1. Scott Miller Post author

      iperf version 2 is no longer working.

      I have had to make the server iperf3 only in part from users abusing iperf v2 connections. I apologize. I will update this post to reflect the change.


      iperf3 is in Fedora repositories.

      Debian and Ubuntu do not have iperf3 in standard repositories yet unfortunately. But it is fairly straightforward to build. I will see if there are any Ubuntu PPAs that offer iperf3.


  16. chandu

    from the output of iperf3 reverse mode (iperf3 -R -c iperf.scottlinux.com), which result is related to download speed.
    is it sender value or receiver value??

    1. Alex

      Hi chandu,

      It is related with both of them. It is a measurement of how fast data can be sent over a network. In reverse mode, server is sending data to client, so it is related with server’s upload and client’s download speed.

  17. Alex

    Hi Scott,

    Your iperf server is really useful. Thanks for this great job.

    I have a problem with reverse mode. From client perspective, UL is finished successfully with a rst, ack. Then DL is started. First packet is coming from server side then client is responding with a RST. Could you please help me to find what the problem is?

    1. Scott Miller Post author

      I am unfortunately not able to reproduce or see that from my testing.

      1. ElleLang

        I’ve the same problem with dual test, server connect to client, and send some packets to client, about 1 second later, client send RST to server. I use JPerf 2.0.2 on Windows 7.

  18. Mirko

    Hi Scott,

    works great, in ipv4 and ipv6. I wanted to figure out whether my provider is capable of full speed in both protocols and your service provided the means.

    Thanks a lot


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