List of the Top 3 Free Network Operating Systems (NOS) in 2025

The CacheGuard product range revolves around a foundational offering known as CacheGuard-OS. When installed on either a physical or virtual machine, CacheGuard-OS effectively converts that system into a robust network appliance. This newly formed appliance can serve multiple functions as various types of gateways that enhance the security and efficiency of your network. Below is a concise overview of the various CacheGuard appliances available. - Web Gateway: exercise control over organizational web traffic and filter out undesirable web access. - UTM (Unified Threat Management): protect your networks from a wide array of online threats using a combination of a firewall, antivirus at the gateway, VPN server, and a filtering proxy. - WAF (Web Application Firewall): prevent harmful requests from reaching your essential web applications and safeguard your enterprise. The WAF incorporates OWASP rules while allowing for the creation of custom rules, along with an IP reputation filtering system that enables the blocking of IPs identified in real-time blacklists. - WAN Optimizer: optimize the flow of your vital network traffic, conserve bandwidth, and ensure high availability for your internet connection through the use of multiple ISPs. Each appliance is designed to address specific network challenges, ultimately providing comprehensive solutions tailored to your organization’s needs.

Open-source software combined with a universal router plays a crucial role in making network access more equitable for all. VyOS aims to transform the way individuals connect to networks, empowering them to create the solutions they envision without facing constraints, limitations, or exorbitant costs. We assert that access to the internet is as vital for human progress as essential resources like food, water, air, and healthcare. Founded by engineers with a passion for innovation, VyOS stands as an open-source company dedicated to facilitating unrestricted network access without financial barriers. Our mission is realized through VyOS, leveraging our open-source software and virtual platforms to provide robust solutions. We offer features such as stateful firewalls, zone-based firewalls, and various types of NAT, including one-to-one, one-to-many, and many-to-many configurations. Moreover, our commitment extends to transparency, allowing users to engage in auditing, create customized images, and contribute to the development, with full access to the entire codebase and build toolchain available to all. This collaborative approach not only enhances security but also fosters a community of innovation and shared knowledge.

FreeBSD is distinguished by its advanced networking capabilities, outstanding performance, robust security features, and compatibility elements that many other operating systems, including several leading commercial options, often lack. It has become a top-tier choice for both Internet and Intranet servers, providing dependable network services even under significant stress while effectively managing memory to guarantee excellent response times for a multitude of concurrent user processes. In addition, FreeBSD's sophisticated operating system capabilities extend to both appliance and embedded systems, supporting a variety of hardware platforms ranging from high-end Intel-based devices to ARM, PowerPC, and MIPS architectures. Worldwide, vendors rely on FreeBSD for their embedded products, which include an array of devices such as mail and web appliances, routers, time servers, and wireless access points, all made possible by its integrated build and cross-build environments. The flexibility of the Berkeley open-source license empowers these vendors to decide how much they wish to contribute back to the community, which encourages collaboration and sparks innovation. Furthermore, this unique blend of features positions FreeBSD as an essential tool for developers who are dedicated to building high-performance embedded solutions that meet the demands of modern technology. Its reputation in the field continues to grow as more users recognize the advantages it brings to various applications.