OpenSSH ProxyCommand equivalent in PuTTY

Solution 1:

You probably don't have the ssh binary on your Windows system.

You can use the plink.exe with the -nc switch instead of the ssh with the -W switch:

An alternative is to open a tunnel via the "NAMEOFHOST" first using an another instance of PuTTY (or Plink).

See for example, my guide for tunneling SFTP/SCP session. It's for WinSCP, but just use PuTTY instead of WinSCP in section Connecting through the tunnel.

Alternatively, you can get ssh.exe from Microsoft build of OpenSSH for Windows. On Windows 10 version 1803 or newer, OpenSSH is built-in. On older versions of Windows 10, you can install it or you can just download a ZIP package. The client tools do not need any installation, you can just extract them.

See also Does OpenSSH support multihop login?