What it does
iperf2 measures network throughput, latency, jitter and loss, with TCP and UDP tests, bidirectional modes and detailed reporting.
Start an iperf2 server, connect a matching client and choose the TCP or UDP traffic mode and rate. Its version 2.2.2 manual includes reverse and full-duplex tests, enhanced reports, CSV output and file redirection. One-way delay needs synchronized clocks; reported byte and packet counts describe what the socket API sees and exclude lower-layer headers and framing. These are measurements between the selected endpoints, rather than a general Internet rating. iperf2 and iperf3 are independent and do not interoperate. Some options, including particular permit-key and UDP L4S features, require the professional build described in the manual.
Strengths
- TCP and UDP testing with bidirectional modes
- Detailed latency and responsiveness measurements
Best for
- Specialized throughput and responsiveness experiments
Sources
- Iperf 2 download | SourceForge.net (Oct 26, 2026)
- Iperf2 User Manual (Oct 26, 2026)