Apps similar to FortiOS include CentOS, which is free and open source. Other options are Red Hat Enterprise Linux, Rocky Linux, SUSE Linux Enterprise and Oracle Solaris. In total there are five Operating Systems like FortiOS for Linux and self-hosting.
CentOS is a community-supported, free and open source operating system based on Red Hat Enterprise Linux. It exists to provide a free enterprise class computing platform and strives to maintain 100% binary compatibility with its upstream distribution.
United States
Red Hat is the leader in development, deployment, and management of Linux and open source solutions for Internet infrastructure - ranging from embedded devices to secure Web servers. Red Hat was founded in 1994 by visionary entrepreneurs Bob Young and Marc Ewing.
United States
Rocky Linux is a community enterprise operating system designed to be 100% bug-for-bug compatible with America's top enterprise Linux distribution now that its downstream partner has shifted direction. It is under intensive development by the community.
United States
SUSE is the original provider of the enterprise Linux distribution and the most interoperable platform for mission-critical computing. It's the only Linux recommended by VMware, Microsoft and SAP. And it's supported on more hardware and software than any other enterprise...
Germany
EU
Oracle Solaris is the #1 enterprise OS, delivering breakthrough high-availability, security, efficiency, and industry-leading scalability/performance.
United States
