Solar-Putty is a great FREE alternative of PuTTY utility made by Solarwinds thats as an SSH Client just like Putty. It does not require installation, it just go straight to work.
PuTTY was primarily written for Windows but with it exponential popularity Port of other operating systems were created.
PuTTY is a free and open-source terminal emulator, serial console and network file transfer application. It supports several network protocols, including SCP, SSH, Telnet, rlogin, raw socket connection and can connect to a serial port. It is widely used to connect, manage and control servers through the internet securely.