iperf for Bandwidth Testing

A file transfer reaches only 180 Mbps across a path expected to support 1 Gbps. Is the network limiting the transfer, or are storage, encryption, and application behavior responsible?

iperf3 helps narrow that question by generating traffic between two controlled endpoints and measuring the rate achieved by the test. It removes file I/O, HTTP, database work, and most application logic from the measurement. The result describes the tested path, direction, protocol, duration, and flow count. It does not establish a universal speed for the network or predict every application's performance.

This distinction makes iperf3 valuable for comparing:

An iperf test deliberately creates load. A maximum-rate run can fill a shared link, increase latency for other users, trigger alerts, and consume substantial CPU. Run it only between systems and across networks you are authorized to test.