This was done as a one-time troubleshooting experiment. May never need it again, but just in case…
Windows PowerShell (as admin), install OpenSSH client:
If needed, use PuttyGen to export the Putty-format key to OpenSSH format.
Windows command line (
-N means “no remote command”):
The console will not show any messages or prompts.
Ctrl-C to close the tunnel.