SSH is one communication protocol that is used to access remote systems all the time. Short for “Secure Shell”, SSH provides a secure channel for data exchange, unlike Telnet and other insecure remote shells. Telnet, e.g., transmits all data including passwords in plain text.
For a system A to connect to a remote system B through SSH, A needs a SSH client (like PuTTY for Windows) and B needs a SSHD server running all the time so as to accept incoming connections.
SSH is a proprietary software offered by SSH Communications Security, and as an alternative the open source version OpenSSH is being widely used. On all Unix-based OSs, the OpenSSH SSHD server is installed by default during the installation of the operating system. On Windows, however, it is not the case.
You can install it on top of Cygwin very easily. You will need administrator access with a password set for the account. When you run the Cygwin setup to download or install various packages, select openssh which will select all the other packages it requires.
Once you complete the install, to configure SSHD run $ ssh-host-config –y from the terminal. This will automatically answer ‘yes’ for the yes/no questions. Give an appropriate password that follows your system rules if an sshd_server is being created or ignore this step. Specify the value of the environment variable CYGWIN as “ntsec tty” for WinXP and Vista and “binmode ntsec tty” for Windows 2003 Server (without quotes). At the end of this process, the sshd service will have automatically started and placed itself among the Windows startup list.