# OpenBSD

> security-focused Unix-like operating system

**Wikidata**: [Q34215](https://www.wikidata.org/wiki/Q34215)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/OpenBSD)  
**Source**: https://4ort.xyz/entity/openbsd

## Summary
OpenBSD is a free, security-oriented Unix-like operating system that forked from the Berkeley Software Distribution in 1995. Led by creator Theo de Raadt, it prioritizes code correctness, proactive security features, and freely redistributable source code under permissive ISC and BSD licenses.

## Key Facts
- Inception date: 18 October 1995
- Creator/Project leader: Theo de Raadt (born 19 May 1968, Canadian/South-African computer scientist)
- License: ISC license (preferred), 3-clause BSD License, BSD licenses
- Mascot: Puffy (a pufferfish)
- Official website: https://www.openbsd.org
- Source code: https://cvsweb.openbsd.org (primary CVS), https://github.com/openbsd/src (Git mirror)
- Based on: 4.4BSD-Lite2 lineage of the Berkeley Software Distribution
- Platforms: amd64, i386, arm64, armv7, sparc64, powerpc, alpha, hppa, luna88k, plus historical ports
- Stable versions cited: 2.3 (1998-05-19), 5.8 (2015-10-18), 5.7 (2015-05-01), 5.6 (2014-11-01)
- Social media: @OpenBSD on Twitter (verified, 11 998 followers as of Feb 2023), subreddit r/openbsd (11 272 subscribers)

## FAQs
### Q: What makes OpenBSD different from other BSDs?
A: OpenBSD emphasizes proactive security auditing, code correctness, and minimal default install. It invents security features like OpenSSH, LibreSSL, and pledge/unveil, and ships with only one tool per task to reduce attack surface.

### Q: Is OpenBSD really free to use and modify?
A: Yes. OpenBSD is released under the permissive ISC and BSD licenses, allowing unrestricted use, copying, modification, and redistribution—including commercial use—without legal encumbrance.

### Q: Which architectures does OpenBSD support?
A: Current tier-1 platforms are amd64, i386, arm64, armv7, sparc64, powerpc, and macppc. Historical ports include DEC Alpha, HP PA-RISC, and LUNA-88k.

### Q: Who leads the project?
A: Theo de Raadt, a Canadian/South-African network engineer, founded and still coordinates the OpenBSD project, overseeing releases and the small core developer team.

## Why It Matters
OpenBSD carved out a unique niche by proving that a small, volunteer team can produce a server-grade operating system whose security record rivals or exceeds those of billion-dollar vendors. Its policy of continuous code auditing—every commit is reviewed for correctness—has uncovered widespread bugs later found in other systems, raising the baseline quality of open-source software everywhere. Technologies created for OpenBSD, most famously OpenSSH, have become invisible infrastructure for the entire Internet. By refusing binary blobs and proprietary drivers, the project also demonstrates that security and user freedom can coexist, influencing policy debates from hardware firmware to government procurement. For administrators who need a minimal, predictable, and aggressively security-hardened platform, OpenBSD remains a gold standard.

## Notable For
- Origin of OpenSSH, now ubiquitous for secure shell access
- Invented LibreSSL fork after Heartbleed, removing 300 000+ lines of obsolete code
- First to ship mandatory stack protection, W^X, and ASLR by default
- Only major OS to offer pledge/unveil system-call sandboxing in base
- Maintains a single, integrated source tree for base system and Xenocara X11, simplifying auditing and customization

## Body
### History and Lineage
OpenBSD forked from NetBSD in October 1995 when Theo de Raadt was removed from NetBSD core. The new project set an explicit goal: "Secure by default." Releases adopted a six-month cadence; version 2.0 appeared 18 Oct 1996, followed by 2.1 (Jun 1997), 2.2 (Dec 1997), 2.3 (May 1998), 2.4 (Dec 1998), 2.5 (May 1999), 2.6 (Dec 1999), and so on through 5.6 (Nov 2014), 5.7 (May 2015), and 5.8 (Oct 2015).

### Security Innovations
OpenBSD introduced:
- StackGhost (stack smash protection) on SPARC (1997)
- W^X (write-xor-execute) memory policy (2003)
- ProPolice stack protector enabled globally (2004)
- Address Space Layout Randomization (ASLR) for userland (2014)
- pledge(2) and unveil(2) sandboxing (2014–2019)

These features are enabled in the base system; third-party ports inherit them automatically.

### Licensing Philosophy
The project prefers the ISC license, a 2-clause permissive license compatible with both GPL and proprietary code. Base system and ports avoid GPL-3 where possible to keep the entire system freely reusable in embedded products.

### Platform Support
Tier-1 (fully supported) architectures are amd64, i386, arm64, armv7, sparc64, powerpc, macppc. Tier-2 include alpha, hppa, luna88k. Platform pages list detailed hardware compatibility and installation notes.

### Ecosystem
Hundreds of third-party packages run on OpenBSD, including Suricata IDS, WireGuard tools, Prism Launcher, Nushell, Jujutsu VCS, and the Go, Crystal, and Hare compilers. Derivatives such as LibertyBSD remove non-free firmware blobs while staying synchronized with OpenBSD releases.

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## References

1. [The UNIX system family tree: Research and BSD](http://bxr.su/d/share/misc/bsd-family-tree)
2. [The UNIX system family tree: Research and BSD](http://bxr.su/DragonFly/share/misc/bsd-family-tree)
3. [Source](http://openbsd.su/src/sys/kern/init_main.c)
4. [Source](http://cvsweb.openbsd.org/cgi-bin/cvsweb/~checkout~/src/sys/kern/init_main.c?rev=1.261&content-type=text/plain)
5. [Source](https://github.com/openbsd/src/blob/master/share/misc/license.template)
6. [Source](http://www.openbsd.org/21.html)
7. [Source](http://www.openbsd.org/22.html)
8. [Source](http://www.monkey.org/openbsd/archive2/announce/199610/msg00001.html)
9. [Source](http://undeadly.org/cgi?action=article&sid=20061019013207)
10. [Source](http://www.openbsd.org/23.html)
11. [OpenBSD 2.3 released. 1998](https://marc.info/?l=openbsd-announce&m=90222459431597&w=2)
12. [Source](http://www.openbsd.org/24.html)
13. [Source](http://www.openbsd.org/25.html)
14. [Source](http://www.openbsd.org/26.html)
15. [Source](http://thread.gmane.org/gmane.os.openbsd.announce/203)
16. [Source](http://www.openbsd.org/57.html)
17. [OpenBSD 5.8. OpenBSD Project. 2015](http://www.openbsd.org/58.html)
18. [OpenBSD 5.8 released. 2015](https://marc.info/?l=openbsd-announce&m=144518039211051&w=2)
19. [Source](http://www.openbsd.org/27.html)
20. [Source](http://www.openbsd.org/28.html)
21. [Source](http://www.openbsd.org/29.html)
22. [Source](http://www.openbsd.org/30.html)
23. [Source](http://www.openbsd.org/31.html)
24. [Source](http://www.openbsd.org/32.html)
25. [Source](http://www.openbsd.org/33.html)
26. [Source](http://www.openbsd.org/34.html)
27. [Source](http://www.openbsd.org/35.html)
28. [Source](http://www.openbsd.org/36.html)
29. [Source](http://www.openbsd.org/37.html)
30. [Source](http://www.openbsd.org/38.html)
31. [Source](http://www.openbsd.org/39.html)
32. [Source](http://www.openbsd.org/40.html)
33. [Source](http://www.openbsd.org/41.html)
34. [Source](http://www.openbsd.org/42.html)
35. [Source](http://www.openbsd.org/43.html)
36. [Source](http://www.openbsd.org/44.html)
37. [Source](http://www.openbsd.org/45.html)
38. [Source](http://www.openbsd.org/46.html)
39. [Source](http://www.openbsd.org/47.html)
40. [Source](http://www.openbsd.org/48.html)
41. [Source](http://www.openbsd.org/49.html)
42. [Source](http://www.openbsd.org/50.html)
43. [Source](http://www.openbsd.org/51.html)
44. [Source](http://www.openbsd.org/52.html)
45. [Source](http://www.openbsd.org/53.html)
46. [Source](http://www.openbsd.org/54.html)
47. [OpenBSD 5.5 Released. 2014](https://marc.info/?l=openbsd-announce&m=139895819502063&w=2)
48. [OpenBSD 5.9](http://www.openbsd.org/59.html)
49. [OpenBSD 5.9 released (early!). OpenBSD Journal. 2016](http://undeadly.org/cgi?action=article&sid=20160329181346)
50. [OpenBSD 6.0](https://www.openbsd.org/60.html)