OpenSSH is a complete implementation of the SSH protocol (version 2) for secure remote login, command execution and file transfer. It includes a client
ssh and server
sshd, file transfer utilities
sftp as well as tools for key generation (
ssh-keygen), run-time key storage (
ssh-agent) and a number of supporting programs.
This is a port of OpenBSD's OpenSSH to most Unix-like operating systems, including Linux, OS X and Cygwin. Portable OpenSSH polyfills OpenBSD APIs that are not available elsewhere, adds sshd sandboxing for more operating systems and includes support for OS-native authentication and auditing (e.g. using PAM).
The official documentation for OpenSSH are the man pages for each tool:
Stable release tarballs are available from a number of download mirrors. We recommend the use of a stable release for most users. Please read the release notes for details of recent changes and potential incompatibilities.
Building Portable OpenSSH
Portable OpenSSH is built using autoconf and make. It requires a working C compiler, standard library and headers, and zlib.
libcrypto from either LibreSSL or OpenSSL may also be used, but OpenSSH may be built without it supporting a subset of crypto algorithms.
FIDO security token support need libfido2 and its dependencies. Also, certain platforms and build-time options may require additional dependencies, see README.platform for details.
Building a release
Releases include a pre-built copy of the
configure script and may be built using:
tar zxvf openssh-X.YpZ.tar.gz cd openssh ./configure # [options] make && make tests
See the Build-time Customisation section below for configure options. If you plan on installing OpenSSH to your system, then you will usually want to specify destination paths.
Building from git
If building from git, you'll need autoconf installed to build the
configure script. The following commands will check out and build portable OpenSSH from git:
git clone https://github.com/openssh/openssh-portable # or https://anongit.mindrot.org/openssh.git cd openssh-portable autoreconf ./configure make && make tests
There are many build-time customisation options available. All Autoconf destination path flags (e.g.
--prefix) are supported (and are usually required if you want to install OpenSSH).
For a full list of available flags, run
configure --help but a few of the more frequently-used ones are described below. Some of these flags will require additional libraries and/or headers be installed.
||Enable PAM support. OpenPAM, Linux PAM and Solaris PAM are supported.|
||Enable libedit support for sftp.|
||Enable Kerberos/GSSAPI support. Both Heimdal and MIT Kerberos implementations are supported.|
||Enable SELinux support.|
||Include built-in support for U2F/FIDO2 security keys. This requires libfido2 be installed.|