PuTTY Guide - optional ways to configure the PuTTY software.PuTTY download and installation instructions.Users of Windows 10, macOS, and Linux can use a pre-installed command-line SSH client. Windows users can download and install the free PuTTY SSH client You will need a Secure Shell (SSH) client to connect to the departmental Unix servers. Accessing hopper.cs.niu.edu Accessing hopper.cs.niu.edu