iperf3

TLDR

Run iperf3 as a server

$ iperf3 -s

Run an iperf3 server on a specific port

$ iperf3 -s -p [port]

Start bandwidth test

$ iperf3 -c [server]

Run iperf3 in multiple parallel streams

$ iperf3 -c [server] -P [streams]

Reverse direction of the test. Server sends data to the client

$ iperf3 -c [server] -R