OpenSSH

OpenSSH was first released in late 1999, and has been actively developed ever since. It is the latest step in a very long and useful history of networked computing, remote access, and telecommuting. The OpenSSH suite provides secure remote access and file transfer.http://www.openssh.com/ OpenSSH www.openssh.com Since its initial release, it has grown to become the most widely used implementation of the SSH protocol. During the first ten years of its existence, it had largely replaced older corresponding unencrypted tools and protocols. The OpenSSH client is included by default in most operating system distributions, including MacOS, AIX, Linux, BSD, and Solaris. Any day you use the Internet, you are using and relying on hundreds if not thousands of machines operated and maintained using OpenSSH. A survey in 2008 showed that of the SSH servers found running, just over 80% were OpenSSH. http://www.openssh.com/usage/ssh-stats.html Statistics from the current scan results OpenSSH.com 2008 Even with the advent of the Internet of Things and the increased use of IPv6, a cursory search of Shodan https://www.shodan.io/search/facet?query=ssh-2.0&facet=product SSH-2.0 Search Results shodan.io 2026-10-13 for SSH 2.0 services, on any port, in October 2026 showed about 93% of responding addresses running OpenSSH. Previously, in November 2022, around 87% of the responding addresses were running OpenSSH. Previously, in November 2022, around 87% of the responding addresses were running OpenSSH. On October 13, 2026, OpenSSH's 93% was 36,841,871 out of 39,640,574 systems. Dropbear made up just over 1% at 469,091 systems and then a long tail filled in the rest. This book is for fellow users of OpenSSH to help save effort and time through using OpenSSH, and especially SFTP, where it makes sense to use it. __NOTOC__ mini OpenSSH OpenSSH Introduction /Overview/ /Why Use Encryption/ /SSH Protocols/ /Other SSH Implementations/ Client-Server /Client Applications/ /Client Configuration Files/ OpenSSH Server /Pattern Matching in OpenSSH Configuration/ Utilities /Utilities/ Third Party Utilities Logging, Troubleshooting, and Development Logging and Troubleshooting /Development/ Cookbook Remote Processes Tunnels Automated Backup File Transfer with SFTP Public Key Authentication Certificate-based Authentication Host-based Authentication Load Balancing Multiplexing Proxies and Jump Hosts References Internet Open source software Computing System administration O 100%