iperf2 review
A free, open-source CLI for detailed cross-platform network performance testing.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
iperf2 is a free, open-source command-line network performance measurement tool from the iperf2 project. It generates and receives TCP or UDP traffic between a client and server, making it suitable for network engineers, developers, and technical teams that need repeatable throughput and transport-level measurements across different environments. Vendor-provided builds and packages support Windows, macOS, Linux, Android, embedded systems, and set-top boxes.
Its main strength is measurement depth within network performance testing. iperf2 covers throughput, latency, jitter, packet loss, ECN, one-way delay, and round-trip measurements. Tests can use parallel streams, bidirectional traffic, reverse traffic, full-duplex operation, and multicast. Support for both IPv4 and IPv6 broadens its usefulness across mixed network environments, while CSV report output can help incorporate results into analysis workflows. TCP congestion-control and socket-pacing tests add further detail for teams investigating transport behavior rather than only checking headline bandwidth.
The trade-off is its narrow focus and command-line workflow. iperf2 is designed for generating traffic and measuring network performance, not for presenting a broader desktop diagnostic suite. Its free, open-source model keeps the tool accessible for technical users who want to read, build, and adapt the source, with no paid tier structure described by the project. Choose iperf2 when cross-platform throughput and packet-level performance measurements are the priority. Teams seeking a more guided interface or wider diagnostic coverage should consider a different type of network diagnostic software.
iperf2 pros and cons
- Where it wins
- Measures TCP/UDP throughput, latency, jitter, and packet loss
- Supports bidirectional, full-duplex, multicast, IPv4, and IPv6 tests
- Runs across Windows, macOS, Linux, Android, and embedded systems
- Where it doesn't
- Command-line operation may require technical networking knowledge
- Focused on performance testing rather than broad network diagnostics
- Vendor-provided builds and packages vary by supported platform
iperf2 fact sheet, pricing and score →
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