iperf3 review
A focused, scriptable throughput tester for Linux and macOS network work.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
iperf3 is an open-source command-line tool for measuring achievable bandwidth between IP hosts. It suits network engineers, developers, research and education networks, and teams building throughput checks into other programs. Client and server operating modes support TCP, UDP, and SCTP testing, with results covering throughput, bitrate, and packet loss. The project is distributed under a three-clause BSD license and is used by perfSONAR, ESnet, and general networking users.
Pricing is straightforward: iperf3 is free and open source. The main setup consideration is distribution. ESnet does not distribute binary packages; its official documentation lists third-party packages and source distributions instead. That makes iperf3 a practical fit for users comfortable with command-line tools, source distributions, or platform package options. Officially supported platforms are Ubuntu Linux, FreeBSD, and macOS, while Windows, Android, and iOS are not officially supported.
Its strongest area is controlled throughput testing rather than broad network diagnosis. Users can configure timing, protocols, and socket buffers, request JSON output, enable zero-copy transmission, and set CPU affinity. The libiperf library also supports embedding functionality in other programs, while perfSONAR provides an ecosystem connection. Choose iperf3 for focused, scriptable bandwidth and packet-loss measurement, especially when embedding or automation matters. Choose another tool if you need path visualization, DNS diagnostics, or officially supported Windows, Android, or iOS deployments.
iperf3 pros and cons
- Where it wins
- Tests TCP, UDP, and SCTP in client or server mode
- Reports throughput, bitrate, and packet loss with optional JSON output
- Supports zero-copy mode, CPU affinity, and the embeddable libiperf library
- Where it doesn't
- Official platform support is limited to Ubuntu Linux, FreeBSD, and macOS
- No built-in path visualization or DNS diagnostics
- ESnet does not distribute binary packages
iperf3 fact sheet, pricing and score →
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