OpenBSD Security, Privacy & Downloads
Discover OpenBSD, its security-focused design and important projects including OpenSSH and LibreSSL. Download OpenBSD releases from our independent community mirror.
What Is OpenBSD?
OpenBSD is a free and open-source Unix-like operating system with a strong emphasis on correctness, security, simplicity, portability and integrated cryptography.
OpenBSD belongs to the BSD family of operating systems and is developed as a complete system. The kernel, system utilities, networking tools and much of the base operating system are maintained together.
This approach provides administrators with a coherent environment, extensive documentation and predictable configuration.
OpenBSD can be used for servers, firewalls, routers, gateways and other network infrastructure. It is also an excellent operating system for learning Unix, networking and system administration.
Why Use OpenBSD?
OpenBSD is designed for people who value security, simplicity, understandable configuration and direct control over their operating system.
OpenBSD develops a carefully integrated base system rather than assembling an operating system entirely from independently maintained components.
For administrators, this can make the operating system easier to understand, audit and maintain.
Secure by Default
OpenBSD emphasizes security-conscious defaults and aims to minimize unnecessary services and exposure on a freshly installed system.
Simple Configuration
Clear configuration files, consistent system utilities and extensive manual pages help administrators understand how the system operates.
Integrated System
The kernel and base operating system are developed together, providing a coherent Unix environment.
Networking
OpenBSD provides extensive networking capabilities and is frequently used for routers, gateways, firewalls and Internet-facing infrastructure.
OpenBSD Security
Security is one of the defining characteristics of OpenBSD. The project has a long history of source-code auditing, defensive programming and exploit mitigation.
Proactive Security
OpenBSD security work is not limited to responding to known vulnerabilities. Developers also audit code and develop defensive mechanisms intended to reduce the impact of software vulnerabilities.
Privilege Separation
OpenBSD applications frequently use privilege separation and privilege reduction.
Software can be divided into components so that only the parts that actually require elevated privileges receive them.
pledge(2)
pledge(2) allows an application to restrict the
categories of system operations that it is permitted to perform.
An application can therefore voluntarily give up capabilities that it does not require.
unveil(2)
unveil(2) allows applications to restrict their
view of the filesystem.
Applications can expose only the files and directories they actually require instead of retaining unrestricted filesystem access.
OpenBSD and Privacy
Privacy depends on applications, network services, configuration and user behaviour as well as the operating system itself.
OpenBSD provides a useful foundation for privacy-conscious infrastructure because administrators retain direct control over installed software, running services and network access.
A minimal system can run only the software and services that are actually required. Reducing unnecessary software can reduce complexity and unnecessary network exposure.
OpenBSD also includes networking, firewall and cryptographic technologies that administrators can use when building systems where control over data and network traffic is important.
PF Firewall
OpenBSD includes PF, its powerful packet-filtering system for controlling network traffic.
PF can be used to build firewalls, gateways and network filtering systems.
Its configuration language is designed to allow administrators to create readable firewall policies.
Combined with OpenBSD's networking stack and related tools, PF makes the operating system particularly interesting for network infrastructure.
OpenBSD Projects
Software developed by the OpenBSD community is used far beyond OpenBSD itself.
OpenSSH
OpenSSH is the OpenBSD project's implementation of the Secure Shell protocol.
It provides encrypted remote login, command execution, tunneling, authentication and secure file transfer.
OpenSSH includes tools such as ssh,
sshd, sftp,
scp, ssh-keygen and
ssh-agent.
LibreSSL
LibreSSL is a TLS and cryptography library maintained by the OpenBSD project.
LibreSSL originated from the OpenSSL code base in 2014. Development has included code cleanup, simplification and security improvements.
OpenSSL and LibreSSL are separate projects. LibreSSL is maintained by the OpenBSD project.
OpenBGPD
OpenBGPD is an implementation of the Border Gateway Protocol used to exchange routing information between autonomous systems on the Internet.
OpenNTPD
OpenNTPD provides network time synchronization with an emphasis on straightforward configuration and secure operation.
OpenSSH — Secure Remote Administration
OpenSSH is one of the best-known technologies originating from the OpenBSD project.
SSH creates an encrypted connection between a client and server. Administrators can use it to access remote systems, execute commands, transfer files and create encrypted tunnels.
ssh
Command-line SSH client for connecting securely to remote systems.
sshd
SSH server daemon responsible for accepting and authenticating connections.
sftp
Secure file-transfer functionality operating through SSH.
ssh-keygen
Utility for generating and managing SSH keys.
LibreSSL — TLS and Cryptography
LibreSSL provides TLS and cryptographic functionality and is maintained by the OpenBSD project.
The project was created in 2014 from the OpenSSL code base. Development has focused on cleaning and simplifying inherited code while improving maintainability and security.
OpenSSL and LibreSSL continue as separate projects.
Download LibreSSL
LibreSSL files distributed through the OpenBSD mirror infrastructure are available from our community mirror.
Browse LibreSSL FilesDownload OpenBSD
OpenBSD.info operates an independent community mirror providing access to OpenBSD releases and related project files.
OpenBSD.info Community Mirror
Browse available OpenBSD releases, architectures and related files directly from our mirror.
Browse OpenBSD MirrorVerify Your Downloads
Operating-system installation files should be verified before use.
OpenBSD publishes signed checksum files that can be used to verify downloaded installation media and release files. Consult the official OpenBSD documentation for current verification instructions.
What Can OpenBSD Be Used For?
Web Servers
Run lightweight Internet-facing websites and services using OpenBSD's integrated networking environment.
Firewalls
Build dedicated firewalls and gateways using PF and OpenBSD's networking tools.
Routers
Deploy routing and network infrastructure using OpenBSD's integrated networking stack.
SSH Gateways
OpenSSH makes OpenBSD an interesting platform for bastion hosts and administration gateways.
DNS Infrastructure
Run DNS and other network services on a small and controlled operating system.
Learning Unix
Extensive manual pages and straightforward configuration make OpenBSD useful for learning Unix administration.
OpenBSD FAQ
Is OpenBSD free?
Yes. OpenBSD is a free and open-source operating system.
Is OpenBSD Linux?
No. OpenBSD is a BSD Unix-like operating system and does not use the Linux kernel.
Is OpenBSD only for firewalls?
No. OpenBSD is a general-purpose Unix-like operating system. Firewalls and networking are popular applications, but it can also run web, DNS, mail and many other services.
What is OpenSSH?
OpenSSH is an implementation of the SSH protocol developed by the OpenBSD project. It provides secure remote login, command execution, tunneling and file-transfer functionality.
What is LibreSSL?
LibreSSL is a TLS and cryptography library maintained by the OpenBSD project. It originated from the OpenSSL code base in 2014.
Is OpenBSD.info an official OpenBSD website?
No. OpenBSD.info is an independent community website and mirror.
The official OpenBSD Project website is www.openbsd.org .
Get Started with OpenBSD
Explore OpenBSD, read the official documentation and download a release from our community mirror.