How to test your network throughput between two devices using iperf3 on Ubuntu 22.04

If you’re looking for an accurate measure of your networking speeds, iperf3 is a great tool to use. UDP tests are more accurate than other types of tests because they don’t rely on the state of the network connection. This means that you’ll get a more accurate measure of the true speeds that your network is capable of. Synchronous speed internet is a type of internet connection where the speeds are the same in both directions. This is opposed to asynchronous speed internet, where the speeds can be different in each direction. Bidirectional synchronous tests are tests that measure the speeds in both directions at the same time. This is important because it gives you a more accurate measure of your network’s true capabilities.

UDP, bidirectional tests are the way to go!

Start by installing iperf3, and running it.

apt install iperf3

Server side

iperf3 -s 

Client side:

iperf3 -V -u -b 930M --bidir -c <iperfserver>  

Will show you additional info. Including the CPU utilization on both sender and receiver.

udp mode

-b 930M

I get about ~930Mbps real world speed when using gigabit networking technology. So I set that as the bandwidth using the -b flag. -b infers -u, so you don’t need to use -u for udp tests. Just -b. Otherwise iperf3 defaults to 1mbps for udp tests.


This flag initializes a bidirectional synchronous test.

-p <portnumber>

Optional: You can use the -p flag to use a custom port. Make sure to set the flag on both server, and client.

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