Farsight review
A specialized open-source scanner for high-rate Internet measurement on Linux.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Farsight is an open-source, stateless SYN-based TCP port scanner and banner grabber written in Rust. It is designed for Linux operators conducting large-scale Internet measurement, with support for scanning the entire IPv4 address space or a subset. The project suits teams that need direct control over deployment and scan behavior rather than a hosted scanning service.
Its strongest technical focus is high-rate, adaptive scanning. Farsight uses AF_XDP and eBPF packet processing, configurable packet-rate limiting, and backpressure controls. Its targeting engine uses historical scan results to prioritize ports and IP prefixes, while automatic honeypot or catch-all detection helps distinguish misleading responses. Application-layer banner parsing extends the output beyond open-port discovery, and Minecraft Server List Ping support covers a specific service-detection use case. Scheduled scans and ClickHouse result storage support recurring measurement workflows.
The trade-off is a specialized operating model. Farsight runs on Linux in a self-hosted deployment and requires Rust nightly, compatible XDP hardware or drivers, and a reachable ClickHouse server. ClickHouse is also the listed integration, so teams seeking a broad connector ecosystem or a managed interface may prefer another tool. Its open-source model avoids a commercial plan structure, but operators still need to provision and maintain the required environment. Choose Farsight when Linux ownership, Internet-wide scope, packet-rate control, and adaptive targeting are priorities; choose an alternative when low-setup deployment or wider platform integration matters more.
Farsight pros and cons
- Where it wins
- Stateless SYN scanning with application-layer banner parsing
- AF_XDP and eBPF processing for high-rate packet handling
- Adaptive targeting, honeypot detection, and ClickHouse storage
- Where it doesn't
- Requires Linux, Rust nightly, and compatible XDP hardware or drivers
- Self-hosted deployment requires a reachable ClickHouse server
- ClickHouse is the only listed integration
Farsight fact sheet, pricing and score →
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