PuTTY is a free, open-source SSH, Telnet, and serial console client that has become the standard terminal emulator for Windows systems. Originally developed by Simon Tatham, PuTTY provides secure remote access to servers and network devices with extensive configuration options.
The software supports SSH protocols including SSH-1 and SSH-2 with RSA and ECDSA key authentication. Telnet, rlogin, and raw socket connections handle legacy systems and network debugging. Serial port support enables communication with local devices.
PuTTY's terminal emulation accurately reproduces xterm, VT102, and other terminal types. Comprehensive keyboard handling includes function keys, numpad, and special sequences. Unicode support displays international characters correctly.
Connection settings stored in sessions enable quick access to frequently used hosts with configured options. The Default Settings session provides consistent configuration across all new connections. Import and export capabilities share configurations between installations.
Security features include SCP and SFTP file transfer through companion applications PSCP and PSFTP. PuTTYgen generates RSA, DSA, ECDSA, and ED25519 key pairs for public key authentication. Pageant provides SSH authentication agent functionality for single sign-on scenarios.
The interface allows color, font, cursor, and window behavior customization. Logging captures session output for documentation and debugging. Port forwarding tunnels connections through SSH for secure access to remote services. X11 forwarding runs graphical Linux applications remotely.