iPerf2

iPerf2 is a self-hosted active network-testing utility for engineers, operators, and labs that control both ends of a connection. It is the right fit when you need deliberately shaped TCP or UDP traffic and measurements beyond a simple speed check. Its broad protocol and reporting controls are balanced by socket-level measurement boundaries and a separate ecosystem from iPerf3.

Overview

Every test uses a server to receive traffic and a client to generate and send it. That architecture gives you repeatable control over direction, protocol, stream count, and load, but it also requires hosts you can configure and reach. iPerf2 therefore suits managed networks, development labs, and troubleshooting work better than casual users looking for an instant public internet test.

The project is free and self-hosted across Android, Linux, macOS, and Windows. SourceForge ticket and discussion pages are the support channels. The Android client described in the manual adds live meters for throughput, latency, and congestion signals, making a phone usable as one endpoint when that is practical.

Key features

Traffic patterns and protocols

TCP and UDP tests can run in one direction, both directions, full duplex, or as simultaneous multi-stream traffic. This lets an engineer distinguish asymmetric behavior from contention between concurrent flows and choose a pattern that mirrors the workload under investigation. The flexibility is valuable, but meaningful results depend on selecting a test arrangement that answers a specific diagnostic question.

IPv4, IPv6, and multicast are supported, including source-specific multicast joins. That makes iPerf2 useful for networks where multicast delivery or dual-stack behavior matters, not just ordinary point-to-point links. UDP L4S support is part of the professional feature set.

Measurements and reporting

Measurements cover throughput, one-way delay, round-trip time, jitter, packet loss, link capacity, and responsiveness. Reports can include enhanced metrics and can be written as CSV, which helps retain runs for later processing or compare results across environments. The important qualification is that metrics come from socket-level reads and writes; lower-level protocol-header overhead is outside the measurement boundary, so these figures should not be treated as a complete wire-level accounting.

Access controls

Permit-key HMAC authentication uses a timestamped HMAC-SHA256 value, with replay limited by a configurable time window. Professional builds add server access gating and remotely enabled server-side latency histograms. The manual describes the professional source as freely available to inspect and build, which favors teams comfortable compiling and operating their own tooling.

iPerf2 and iPerf3 are independent implementations and do not interoperate. A team standardizing on iPerf3 endpoints cannot assume an iPerf2 client or server will join those tests.

Pricing

Plan	Price	What it includes
Community edition	free	TCP and UDP testing, throughput and latency metrics, multicast, and IPv4/IPv6 support.
Professional edition	free	Compile-time feature set, permit-key access gating, server-side latency histograms, and UDP L4S support.

Both editions are free, with no paid tier or seat and quota terms presented. Community is the straightforward choice for standard active testing; Professional is for operators who need gated server access, histogram output, or UDP L4S and can manage compile-time features. The free price does not remove the operational work of deploying and maintaining both endpoints.

Platforms

iPerf2 runs on Android, Linux, macOS, and Windows, with self-hosted deployment. Its active model is platform-agnostic only after you have a reachable client/server pair; endpoint setup remains part of the job.

Who it's for

Choose iPerf2 for network operators validating links, developers reproducing transport behavior, and labs investigating delay, loss, jitter, multicast, or dual-stack performance under controlled traffic. It is also suitable when CSV output or custom traffic direction matters. Look elsewhere if you need passive monitoring, a hosted measurement service, or guaranteed interoperability with iPerf3.

Pros and cons

• Pros: Broad TCP and UDP traffic modes expose directional, duplex, and multi-stream behavior.
• Pros: One-way delay, RTT, jitter, loss, throughput, multicast, IPv4, and IPv6 cover demanding diagnostic cases.
• Pros: CSV and enhanced reporting support repeatable analysis outside the tool.
• Pros: Free professional controls add HMAC-based gating and latency histograms without a license charge.
• Cons: Both a generating client and receiving server are required, adding deployment overhead.
• Cons: Socket-level measurements exclude lower-layer protocol-header overhead.
• Cons: iPerf2 cannot exchange tests with iPerf3.

Alternatives

Network Testing Software is the broader category for comparing tools. Pick OpenSpeedTest instead when a free HTML5 test, web access, or an embeddable widget matters more than iPerf2's protocol control. LibreSpeed is another free, self-hosted option with no paid plans listed, suited to a simpler browser-oriented deployment.

PingPlotter is the better choice for ongoing path monitoring: its free tier allows one connection and 10 minutes of history, while Professional Edition costs $29 a month. Choose TRex for open-source Linux traffic generation when its hardware and NIC requirements fit. EVE-NG suits virtual network labs, with a free tier capped at 7 nodes per instance and 63 per lab; paid Base licensing uses custom pricing.

Mininet is preferable for emulated networks when Linux is available and one server's CPU and bandwidth are sufficient. GNS3 is a free, open-source choice for broader network emulation. Netperf fits readers wanting source distribution under the MIT license, accepting that some platform and test features require configuration.

Verdict

iPerf2 is a strong choice for technical users who can operate both endpoints and need free, active TCP/UDP diagnostics across IPv4, IPv6, and multicast. Choose it for controlled traffic patterns and detailed delay, loss, jitter, and throughput data; look elsewhere when wire-level accounting, passive monitoring, hosted simplicity, or iPerf3 compatibility is essential.