A dedicated list of free iperf3 test servers is available at iPerf3 Server List, but sometimes the load on the site is so great it's unreachable.
By default, the iperf3 server listens on TCP port 5201 for connections from an iperf3 client.
iperf3 -v. There are a wide array of options when running iperf3 in Terminal on macOS, but the simplest command is:.
Once running, iperf3 will display test results in the Terminal with each test line showing the test interval (delay in seconds), amount of data, and overall throughput.
Although iperf3 is not backward compatible, iperf2 and iperf3 commands are very similar.
