FreeBSD
FreeBSD offers advanced networking, performance, security and compatibility features today which are still missing in other operating systems, even some of the best commercial ones. FreeBSD makes an ideal Internet or Intranet server. It provides robust network services under the heaviest loads and uses memory efficiently to maintain good response times for thousands of simultaneous user processes. FreeBSD brings advanced network operating system features to appliance and embedded platforms, from higher-end Intel-based appliances to ARM, PowerPC, and MIPS hardware platforms. From mail and web appliances to routers, time servers, and wireless access points, vendors around the world rely on FreeBSD’s integrated build and cross-build environments and advanced features as the foundation for their embedded products. And the Berkeley open source license lets them decide how many of their local changes they want to contribute back.
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NetBSD
NetBSD is a free, fast, secure, and highly portable Unix-like Open Source operating system. It is available for a wide range of platforms, from large-scale servers and powerful desktop systems to handheld and embedded devices. NetBSD was originally released in 1993. Over time, its code has found its way into many surprising environments, on the basis of a long history of quality, cleanliness, and stability. The NetBSD code was originally derived from 4.4BSD Lite2 from the University of California, Berkeley. NetBSD is an entirely free and open-source UNIX-like operating system developed by an international community. It isn't a "distribution" or variant but has evolved over several decades to be a complete and unique operating system in the BSD family. NetBSD users enjoy a simple, well-documented, and fully integrated UNIX-like system that feels minimal, and in many ways traditional, while including many modern and interesting features, and support for recent hardware.
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OpenSSH
OpenSSH is the premier connectivity tool for remote login with the SSH protocol. It encrypts all traffic to eliminate eavesdropping, connection hijacking, and other attacks. In addition, OpenSSH provides a large suite of secure tunneling capabilities, several authentication methods, and sophisticated configuration options. Remote operations are done using ssh, scp, and sftp. Key management with ssh-add, ssh-keysign, ssh-keyscan, and ssh-keygen. The service side consists of sshd, sftp-server, and ssh-agent. OpenSSH is developed by a few developers of the OpenBSD project and made available under a BSD-style license. OpenSSH is incorporated into many commercial products, but very few of those companies assist OpenSSH with funding. Contributions towards OpenSSH can be sent to the OpenBSD Foundation. Since telnet and rlogin are insecure, all operating systems should ship with support for the SSH protocol included. The SSH protocol is available in two incompatible varieties, SSH 1 and SSH 2.
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Qubes OS
Qubes OS is a free and open-source, security-oriented operating system for single-user desktop computing. Qubes OS leverages Xen-based virtualization to allow for the creation and management of isolated compartments called qubes. These qubes, which are implemented as virtual machines (VMs), have specific Purposes with a predefined set of one or many isolated applications, for personal or professional projects, to manage the network stack, the firewall, or to fulfill other user-defined purposes. Qubes brings to your personal computer the security of the Xen hypervisor, the same software relied on by many major hosting providers to isolate websites and services from each other. Can't decide which Linux distribution you prefer? Still, need that one Windows program for work? With Qubes, you're not limited to just one OS. With Whonix integrated into Qubes, using the Internet anonymously over the Tor network is safe and easy.
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