# OpenBSD PF

> firewall program for BSD systems

**Wikidata**: [Q311404](https://www.wikidata.org/wiki/Q311404)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/PF_(firewall))  
**Source**: https://4ort.xyz/entity/openbsd-pf

## Summary
OpenBSD PF is a firewall program for BSD systems, designed to monitor and control incoming and outgoing network traffic based on predefined security rules. It is developed by the OpenBSD Project and serves as a successor to IPFilter, known for its simplicity, security, and integration with the BSD operating system.

## Key Facts
- **Instance of**: Open-source software and firewall.
- **Aliases**: PF, pf.4, pf firewall, packet filter, pf(4), pfctl.
- **License**: BSD licenses.
- **Website**: [https://www.openbsd.org/faq/pf/index.html](https://www.openbsd.org/faq/pf/index.html).
- **Replaces**: IPFilter.
- **Developer**: OpenBSD Project.
- **Publication date**: December 1, 2001.
- **Programming language**: C (as inferred from source code references).
- **Source code repository**: [https://cvsweb.openbsd.org/src/](https://cvsweb.openbsd.org/src/).
- **Wikipedia title**: PF (firewall).
- **Wikipedia languages**: Available in 10 languages (cs, de, en, es, fa, fr, it, ja, ko, mr).

## FAQs
### Q: What is OpenBSD PF used for?
A: OpenBSD PF is used as a network security system to monitor and control incoming and outgoing network traffic based on predefined security rules. It is integrated into BSD systems to enhance security and manage network access.

### Q: Who developed OpenBSD PF?
A: OpenBSD PF was developed by the OpenBSD Project, a community-driven initiative focused on creating secure, reliable, and open-source operating systems.

### Q: Is OpenBSD PF open-source?
A: Yes, OpenBSD PF is open-source software licensed under BSD licenses, allowing users to freely use, modify, and distribute the software.

### Q: What does OpenBSD PF replace?
A: OpenBSD PF replaces IPFilter, another firewall software, known for its simplicity and integration with BSD systems.

### Q: Where can I find the source code for OpenBSD PF?
A: The source code for OpenBSD PF is available in the OpenBSD CVS repository at [https://cvsweb.openbsd.org/src/](https://cvsweb.openbsd.org/src/).

## Why It Matters
OpenBSD PF is significant in the field of network security as it provides a robust and flexible firewall solution for BSD systems. Its development by the OpenBSD Project emphasizes security and simplicity, making it a preferred choice for users who prioritize these aspects. By replacing IPFilter, OpenBSD PF continues to evolve, offering enhanced features and integration with the BSD operating system. Its open-source nature allows for community contributions and customization, further strengthening its role in network security. OpenBSD PF plays a crucial role in protecting systems from unauthorized access and managing network traffic efficiently.

## Notable For
- **Successor to IPFilter**: OpenBSD PF is noted as the successor to IPFilter, inheriting its simplicity and security features while improving integration with BSD systems.
- **Open-Source Development**: Developed by the OpenBSD Project, it benefits from a community-driven approach, ensuring continuous updates and improvements.
- **BSD Integration**: Designed specifically for BSD systems, OpenBSD PF leverages the strengths of the BSD operating system to provide a secure and efficient firewall solution.
- **BSD Licenses**: Licensed under BSD licenses, it allows for free use, modification, and distribution, promoting open-source principles.
- **Wikipedia Recognition**: OpenBSD PF has a dedicated Wikipedia page, indicating its widespread recognition and usage in the cybersecurity community.

## Body
### Overview
OpenBSD PF is a firewall program for BSD systems, developed by the OpenBSD Project. It serves as a network security system to monitor and control incoming and outgoing network traffic based on predefined security rules. The software is known for its simplicity, security, and integration with the BSD operating system.

### Development and History
OpenBSD PF was first published on December 1, 2001. It was developed as a successor to IPFilter, another firewall software, to enhance security and functionality within BSD systems. The OpenBSD Project, a community-driven initiative, continues to develop and maintain OpenBSD PF, ensuring its relevance and effectiveness in network security.

### Technical Details
OpenBSD PF is written in the C programming language, as evidenced by its source code references. The source code is available in the OpenBSD CVS repository, allowing users to access and modify the software as needed. The software is licensed under BSD licenses, promoting open-source principles and community contributions.

### Availability and Usage
OpenBSD PF is available in multiple languages on Wikipedia, indicating its widespread recognition and usage. Users can find detailed information and documentation on the OpenBSD Project's website, which serves as a primary resource for understanding and implementing OpenBSD PF in network security setups.

## References

1. [Source](http://openbsd.su/src/sys/net/pfvar.h)
2. [Source](http://www.benzedrine.ch/pf.html)
3. [Source](http://openbsd.su/src/sys/net/)
4. [Source](http://openbsd.su/src/sbin/pfctl/)
5. Freebase Data Dumps. 2013