PuTTY is a free and open source terminal emulator application which can act as a client for the SSH, Telnet, rlogin, and raw TCP computing protocols and as a serial console client. The name "PuTTY" has no definitive meaning, though 'tty' is the name for a terminal in the Unix tradition, usually held to be short for teletype.
How to use Putty Video
How to use Putty
If you are having a problem using ssh to a machine and it will not allow you to enter a password try this below:
Connection --> SSH --> Auth --> uncheck "Attempt Kerberos 5 GSSAPI/SSPI auth (SSH-2)" or Connection --> SSH --> Auth --> GSSAPI --> uncheck "Allow GSSAPI Authentication (SSH-2 only)"