1# Portable OpenSSH 2 3[](https://github.com/openssh/openssh-portable/actions/workflows/c-cpp.yml) 4[](https://bugs.chromium.org/p/oss-fuzz/issues/list?sort=-opened&can=1&q=proj:openssh) 5[](https://scan.coverity.com/projects/openssh-portable) 6 7OpenSSH 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 ``scp`` and ``sftp`` as well as tools for key generation (``ssh-keygen``), run-time key storage (``ssh-agent``) and a number of supporting programs. 8 9This is a port of OpenBSD's [OpenSSH](https://openssh.com) 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). 10 11## Documentation 12 13The official documentation for OpenSSH are the man pages for each tool: 14 15* [ssh(1)](https://man.openbsd.org/ssh.1) 16* [sshd(8)](https://man.openbsd.org/sshd.8) 17* [ssh-keygen(1)](https://man.openbsd.org/ssh-keygen.1) 18* [ssh-agent(1)](https://man.openbsd.org/ssh-agent.1) 19* [scp(1)](https://man.openbsd.org/scp.1) 20* [sftp(1)](https://man.openbsd.org/sftp.1) 21* [ssh-keyscan(8)](https://man.openbsd.org/ssh-keyscan.8) 22* [sftp-server(8)](https://man.openbsd.org/sftp-server.8) 23 24## Stable Releases 25 26Stable release tarballs are available from a number of [download mirrors](https://www.openssh.com/portable.html#downloads). We recommend the use of a stable release for most users. Please read the [release notes](https://www.openssh.com/releasenotes.html) for details of recent changes and potential incompatibilities. 27 28## Building Portable OpenSSH 29 30### Dependencies 31 32Portable OpenSSH is built using autoconf and make. It requires a working C compiler, standard library and headers. 33 34``libcrypto`` from either [LibreSSL](https://www.libressl.org/) or [OpenSSL](https://www.openssl.org) may also be used. OpenSSH may be built without either of these, but the resulting binaries will have only a subset of the cryptographic algorithms normally available. 35 36[zlib](https://www.zlib.net/) is optional; without it transport compression is not supported. 37 38FIDO security token support needs [libfido2](https://github.com/Yubico/libfido2) and its dependencies and will be enabled automatically if they are found. 39 40In addition, certain platforms and build-time options may require additional dependencies; see README.platform for details about your platform. 41 42### Building a release 43 44Releases include a pre-built copy of the ``configure`` script and may be built using: 45 46``` 47tar zxvf openssh-X.YpZ.tar.gz 48cd openssh 49./configure # [options] 50make && make tests 51``` 52 53See the [Build-time Customisation](#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. 54 55### Building from git 56 57If building from git, you'll need [autoconf](https://www.gnu.org/software/autoconf/) installed to build the ``configure`` script. The following commands will check out and build portable OpenSSH from git: 58 59``` 60git clone https://github.com/openssh/openssh-portable # or https://anongit.mindrot.org/openssh.git 61cd openssh-portable 62autoreconf 63./configure 64make && make tests 65``` 66 67### Build-time Customisation 68 69There 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). 70 71For 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. 72 73Flag | Meaning 74--- | --- 75``--with-pam`` | Enable [PAM](https://en.wikipedia.org/wiki/Pluggable_authentication_module) support. [OpenPAM](https://www.openpam.org/), [Linux PAM](http://www.linux-pam.org/) and Solaris PAM are supported. 76``--with-libedit`` | Enable [libedit](https://www.thrysoee.dk/editline/) support for sftp. 77``--with-kerberos5`` | Enable Kerberos/GSSAPI support. Both [Heimdal](https://www.h5l.org/) and [MIT](https://web.mit.edu/kerberos/) Kerberos implementations are supported. 78``--with-selinux`` | Enable [SELinux](https://en.wikipedia.org/wiki/Security-Enhanced_Linux) support. 79 80## Development 81 82Portable OpenSSH development is discussed on the [openssh-unix-dev mailing list](https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev) ([archive mirror](https://marc.info/?l=openssh-unix-dev)). Bugs and feature requests are tracked on our [Bugzilla](https://bugzilla.mindrot.org/). 83 84## Reporting bugs 85 86_Non-security_ bugs may be reported to the developers via [Bugzilla](https://bugzilla.mindrot.org/) or via the mailing list above. Security bugs should be reported to [openssh@openssh.com](mailto:openssh.openssh.com). 87
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