# iperf3 > Traffic generator for testing network bandwidth. > More information: . - Run iperf3 as a server: `iperf3 {{[-s|--server]}}` - Run an iperf3 server on a specific port: `iperf3 {{[-s|--server]}} {{[-p|--port]}} {{port}}` - Start bandwidth test: `iperf3 {{[-c|--client]}} {{server}}` - Run iperf3 in multiple parallel streams: `iperf3 {{[-c|--client]}} {{server}} {{[-P|--parallel]}} {{streams}}` - Reverse direction of the test. Server sends data to the client: `iperf3 {{[-c|--client]}} {{server}} {{[-R|--reverse]}}`