Openwall GNU/*/Linux

Openwall GNU/*/Linux (or Owl for short) is a security-enhanced server platform. The primary approaches to security are proactive source code review, privilege reduction, privilege separation, careful selection of third-party software, safe defaults, "hardening" to reduce the likelihood of successful exploitation of security flaws, and the uses of "strong" cryptography. Also available are policy enforcement and integrity checking capabilities.

Besides the security enhancements, other key properties of Owl include the ability to rebuild the entire system from source with one simple command ("make buildworld"), support for software packages found in or developed for Red Hat's and compatible Linux distributions, and support for multiple architectures (currently x86, x86-64, SPARC, and Alpha).