.ppk file: how to open it on Windows

2 Windows apps register the .ppk extension. Install one of them to open the file with a double-click.

• 
  PuTTY

  A free implementation of SSH and Telnet for Windows and Unix platforms, along with an xterm terminal emulator.

  Open source 0.85.0.0 5.3M ↓
• 
  PuTTY CAC

  Windows Secure Shell Client With Support For Smart Cards & Certificates

  Open source 0.85.2.0 35.7K ↓ ★ 581

Related guide: Change the default app for a file type in Windows