Farsight

Free plan Linux

What Farsight is

Farsight is a free, self-hosted Linux tool for scanning TCP ports and collecting service banners with SYN-based probes. It can cover IPv4 address space or a configured subset, then store results in ClickHouse. The accumulated results also guide later scans: its PMap-derived targeting method prioritizes ports and IP prefixes. Farsight runs as a configuration-driven daemon, alternating broad sweeps with rescans, and can detect hosts returning the same banner across ports so it stops spending their remaining port budget. Minecraft Server List Ping is its only implemented application protocol, though parser and payload traits provide a way to add others.

Operators can set a global packet-rate ceiling, configure a per-address port budget, and exclude CIDR ranges, IP ranges, or individual addresses. Farsight currently supports IPv4 only. It requires Linux with AF_XDP support, Rust nightly, a supported NIC and driver, root or equivalent runtime capabilities, and a reachable ClickHouse server. The project reports saturating a 1 Gbps link in a test using an Intel I225-V NIC and igc driver.

Who it suits

Farsight suits operators who need self-hosted internet-wide or targeted IPv4 TCP scanning and can provide the required Linux, network hardware, and ClickHouse setup. Its controls may also suit teams that need to manage scan rates and excluded addresses.

What it does well

Scans all IPv4 addresses or a configured subset.
Uses accumulated ClickHouse results to guide targeting.
Supports packet-rate limits and address exclusions.
Detects repeated banners and limits further probing.
MIT-licensed, with protocol extension traits.

What to know first

IPv4 only; no IPv6 support listed.
Minecraft Server List Ping is the only implemented protocol.
Requires Rust nightly and supported AF_XDP hardware.
Requires a reachable ClickHouse server.

Limits

Farsight currently supports IPv4 only, and Minecraft Server List Ping is its only implemented application protocol. It also requires a reachable ClickHouse server to store results and seed targeting graphs.

Getting started

Open the Farsight repository on GitHub.
Prepare Linux with AF_XDP support, Rust nightly, and a supported NIC and driver.
Provide root or equivalent capabilities at runtime.
Set up a reachable self-hosted or managed ClickHouse server.
Configure the scan scope, rate ceiling, port budget, and exclusions.
Run the configuration-driven daemon.

Verdict

Farsight combines configurable SYN scanning with historical targeting and banner collection, but deployment requires several technical dependencies. Its current scope is IPv4, and Minecraft Server List Ping is its sole implemented application protocol.

Questions

How much does Farsight cost?

Farsight is free, with a Free plan.

Which platforms does it support?

It runs on Linux and requires AF_XDP support, Rust nightly, a supported NIC and driver, and root or equivalent runtime capabilities.

What does it scan?

It scans TCP ports across IPv4, either across the full address space or a configured subset.

Which application protocols does it handle?

Minecraft Server List Ping is the only application protocol currently implemented. Other protocols can be added through parser and payload traits.

Does it require a database?

Yes. A reachable self-hosted or managed ClickHouse server is required to store results and seed targeting graphs.

Is Farsight open source?

The repository identifies its license as MIT.

Facts from Farsight's own pages

Adaptive scanning: Its PMap-derived targeting strategy uses accumulated ClickHouse results to guide which ports and IPv4 prefixes to scan. · github.com, 9 Oct 2026
Adaptive targeting: Its PMap-derived targeting strategy learns from accumulated ClickHouse results to prioritize ports and IP prefixes. · github.com, 8 Oct 2026
Configuration: The scanner is configuration-driven and runs as a long-lived daemon that alternates full sweeps and rescans. · github.com, 8 Oct 2026
Database requirement: A reachable self-hosted or managed ClickHouse server is required to store results and seed targeting graphs. · github.com, 8 Oct 2026
Data storage: Farsight writes scan results to ClickHouse, which it also uses as the source of historical data for its targeting strategy. · github.com, 9 Oct 2026
Exclusions: Operators can exclude CIDR ranges, IP ranges, or individual addresses using exclude.conf. · github.com, 9 Oct 2026
Extensibility: Other protocols can be added through parser and payload traits. · github.com, 8 Oct 2026
Honeypot detection: It detects hosts returning identical banners repeatedly and abandons the remaining port budget for those hosts. · github.com, 9 Oct 2026
License: The repository identifies its license as MIT. · github.com, 9 Oct 2026
Opt-out: The maintainer says to request exclusion from mainstream Farsight scanning by emailing [email protected] or submitting a pull request to exclude.conf. · github.com, 8 Oct 2026
Opt-out contact: The README says to contact [email protected] or submit a pull request changing exclude.conf to request scanning-range opt-out. · github.com, 9 Oct 2026
Performance: The project reports saturating a 1 Gbps link in a test using an Intel I225-V with the igc driver. · github.com, 9 Oct 2026
Protocol support: Minecraft Server List Ping is the only implemented application protocol; the README describes traits for adding others. · github.com, 9 Oct 2026
Purpose: Farsight is a stateless SYN-based TCP scanner and banner grabber built on Linux AF_XDP. · github.com, 9 Oct 2026
Rate limiting: The configurable controller.max_rate sets a global packets-per-second ceiling. · github.com, 9 Oct 2026
Requirements: It requires Linux with AF_XDP support, a compatible XDP-capable NIC and driver, Rust nightly, bpf-linker, runtime capabilities, and a reachable ClickHouse server. · github.com, 9 Oct 2026
Results storage: Farsight writes scan results to ClickHouse, which also supplies history for its targeting strategy. · github.com, 8 Oct 2026
Safety controls: It supports address exclusion lists and a configurable per-address port budget, and its documentation advises honoring opt-outs and keeping scan rates reasonable. · github.com, 8 Oct 2026
Scanning: It can scan the entire IPv4 address space or a configured subset. · github.com, 8 Oct 2026
Scope limit: Farsight currently supports IPv4 only. · github.com, 8 Oct 2026
Scope limitation: The README lists IPv4 only and Minecraft SLP only as current limitations. · github.com, 9 Oct 2026

Where Farsight stands on Freedom251

Port Scanner Software#16 of 26