iperf3 is useful for testing the network throughput of your local network. It can help to indicate network bandwidth of individual nodes on your LAN. Do you have one computer that seems perpetually slow? Then iperf3 may be able to confirm this potential issue.

A WAN speedtest service like Google's will not necessarily indicate the speed of individual nodes on your LAN. Rather, it is better suited to testing the throughput from your home to the public Internet.

Install iperf3 on both the server and client. On Ubuntu you may need to enable the universe repository.

sudo apt-get install iperf3

Run these commands on your iperf3 server.

Create a service at /etc/systemd/system/iperf3.service that will run the server.

[Unit]
Description=iperf3

[Service]
ExecStart=/usr/bin/iperf3 --server

[Install]
WantedBy=multi-user.target

Enable the service.

sudo systemctl enable iperf3

Start the service.

sudo systemctl start iperf3

Verify that the service is running.

sudo systemctl status iperf3

Note the IP address of the server.

ip addr

Run these commands on the client to test network throughput.

Note, you must replace the IP address below with the IP address of your iperf3 server.

Client download test.

iperf3 \
	--reverse \
	--format m \
	--version4 \
	--client 192.168.1.143

Client upload test.

iperf3 \
	--format m \
	--version4 \
	--client 192.168.1.143

Sources