OpenSSH is a 100% complete, freely distributed, and open-source Secure Shell (SSH) 2.0 protocol implementation for GNU/Linux and UNIX-like operating systems. It comes pre-installed with SFTP client and server support, as well as transitional support for the legacy SSH 1.3 and SSH 1.5 protocols, which can be enabled during compilation. The new release, OpenSSH 7.3, is a massive one, bringing all sorts of improvements to security and portability, fixes for many of the bugs reported by users since the previous release, OpenSSH 7.2, as well as a bunch of new features that would make the project even more usable in various security-related scenarios.