
There are many different open source licenses but they all must comply with the Open Source Definition - in brief: the software can be freely used, modified and shared. Programs released under this license can be used at no cost for both personal and commercial purposes. Open Source software is software with source code that anyone can inspect, modify or enhance. Freeware products can be used free of charge for both personal and professional (commercial use).


In really simple terms: you run PuTTY on a Windows machine and tell it to connect to (for example) a Unix machine.

PuTTY 64 bit implements the client end of that session: the end at which the session is displayed, rather than the end at which it runs. These protocols are all used to run a remote session on a computer, over a network. It is written and maintained primarily by Simon Tatham. PuTTY is a free implementation of Telnet and SSH for Windows and Unix platforms, along with an xterm terminal emulator.
