iperf – testing network bandwidth

Iperf — cross-platform console client-server program – a TCP and UDP traffic generator for testing network bandwidth.

The installation command in Ubuntu:

sudo apt-get install iperf

In CentOS:

sudo yum install iperf

To display help in the console, type:

iperf --help

Let’s see what version was installed:

iperf -v

To test network bandwidth, the following commands are executed:

On server:

iperf -s -i1

On the client:

iperf -c HOST -t 5

On the client from Windows, you can run the bat file, the pause command will prevent the window from closing:

iperf -c HOST -t 5

You can download the version for Windows on the website iperf.fr
If iperf 2 is installed on the server, then the same is downloaded for Windows. The client of the third version did not connect to the server on the second one.
I also noticed that different versions of the server and client show an incorrect speed!

I’ll describe some startup options:
-i (statistics update interval)
-s (running in server mode)
-c (running in client mode)
-p (manual port specification, standard 5001 TCP)
-D (start the server as a daemon)
-t (test time, standard 10 seconds)

Suppose we run the server as a daemon:

iperf -s -D

Press Ctrl+C to exit, the server will work in the background to complete it, see PID commands and finish:

sudo ps ax | grep iperf
sudo netstat -tulpn | grep :5001
sudo kill -9 PID

See also my articles:
IPTables rules for Iperf
Installing and using Speedtest CLI

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