OpenSSHs

OpenSSH is a suite of secure networking utilities that implement the SSH protocol for secure remote login, file transfers, and other secure network services. It includes both client and server programs and is widely used on Unix-like systems.

OpenSSH originated from the SSH protocols created by Tatu Ylönen in the 1990s; the OpenSSH project began within the OpenBSD project in 1999 to provide a secure, BSD-licensed version. It is now maintained by the OpenSSH team in collaboration with OpenBSD and released as open-source software. Updates and security advisories are provided by the project, with code hosted on the OpenBSD site and mirrored in other repositories.

The suite comprises the ssh client, sshd server, and auxiliary tools such as scp, sftp, ssh-keygen, ssh-agent, ssh-add, and ssh-keyscan. It supports public key authentication, password authentication, and host-based authentication; supports TCP port forwarding (dynamic, local, remote), X11 forwarding; uses strong cryptography with SSH protocol version 2 as the default and recommended; supports a range of ciphers, MACs, and key exchange methods.

OpenSSH is commonly bundled in Unix-like operating systems and many network appliances; it is a standard for secure remote administration and file transfer, and is widely used for tasks such as remote server management and Git over SSH. Security best practices emphasize using SSH-2, disabling password login in favor of key-based authentication, keeping software up to date, and managing keys with agents.

OpenSSH is released under a BSD-style license and is free software; its source is openly available and the project releases regular updates. It is cross-platform but most widely available on Linux, BSDs, macOS, and other platforms.