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Security Onion vs Zeek: catalog facts
Security Onion	Zeek
Freemium The platform is free, while Onion AI features are offered through sales representatives.	Free The software is free under its open-source licence. Hosting, hardware and external…
Linux, Self-hosted	macOS, Linux
Complete monitoring platform installed from a single ISO Includes packet capture, detection rules and threat hunting	Protocol analysers produce semantic logs of what happened on the network rather than raw packets, and its scripting…
Needs dedicated hardware or virtual machines and setup time Onion AI details are only available through sales	It produces a large volume of logs that need somewhere to go, and writing custom detections means learning…
Self-hosted, Operating system	Downloadable app
Closed source	Open source
License not stated	License: BSD-3-Clause
Not stated if an account is needed	Not stated if an account is needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Checked September 23, 2026	Official website Full listing and sources Checked September 22, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.