How to do a speed test

Due to many false positives and the way speedtest.net is being used to test we hereby give you a better solution to test your network speed.

The speedtest.net application uses only one transfer thread with a single server. As we don’t know the actual network load or speed of the nearest speedtest.net server this is bad practice for testing 1G or 10G network performance.

We recommend the use of iperf3 to test the network speed of your server.

Linux (CentOS/AlmaLinux/Ubuntu)

First, we need to install iperf3 on your system.

Download iperf3

CentOS 7/8 & AlmaLinux:

yum install iperf3 epel-release

Ubuntu 18.04/20.04/22.04

apt-get install iperf3

Run the test

You can run a simple iperf3 test by running the following command:

/usr/bin/iperf3 -c iperf.worldstream.nl

We do however suggest a slightly different test with some additional parameters to run over a longer time to get more accurate results:

/usr/bin/iperf3 -c iperf.worldstream.nl -P 8 -t 60 -i 0

iperf3 runs an upload test by default, you are also able to test de download speed by adding the -R tag

/usr/bin/iperf3 -c iperf.worldstream.nl -P 8 -t 60 -i 0 -R

VMWare ESXi

First, we need to access the VMware CLI, this can be done through Out-of-Band management or SSH.

For this example, we will use SSH.

Log in to VMWare to your web panel and enable SSH access, you can find this at Host > Actions > Services > Enable Secure Shell (SSH)

After this is done, we can connect to the server through SSH. On Linux and Mac, this will be native within the terminal. for Windows, you will need a client like Putty. For this example, we will use putty on windows. Connect to the IP of the VMware host with ssh port 22.

After you have been connected we first need to disable the firewall

esxcli network firewall set --enabled false

You can now run the upload test by running the following command:

/usr/lib/vmware/vsan/bin/iperf3 -c iperf.worldstream.nl -t 60 -P 8 -i 0 -4

For the download test use the following command:

/usr/lib/vmware/vsan/bin/iperf3 -c iperf.worldstream.nl -t 60 -P 8 -i 0 -4 -R

When you are done, do not forget to re-enable the firewall again:

esxcli network firewall set --enabled true

And disable SSH access through the Web panel.

Windows

First download iPerf from their website: https://iperf.fr/iperf-download.php

After the ZIP archive has been downloaded, we will need to extract this.

Copy the files cygwin1.dll and iperf3 inside this folder to your C:\Windows\System32 folder.

When this is done, iperf3 will be installed.

To run a test, open a cmd prompt (Windows key + R > cmd.exe) and run the following command:

iperf3 -c iperf.worldstream.nl

Optional

Here you can find a description of some of the useful parameters you can change.

parameter	function
-p	Server port to listen/connect to
-P	Number of parallel client streams to run
-t	Time in seconds to transmit for (default 10 seconds)
-i	Interval: Seconds between periodic bandwidth reports