I have added this request to the tracker:
Issue 2143 – Support for connection sharing
You can vote for it there.

I want to see this included in WinSCP for more than one reason:

1. To not sharing passwords when certificates aren't supported. When reusing the connections of a PuTTY session you don't need to do any new authentication or know the password.
   
2. To connect to Docker containers when using the psusan protocol.
   
3. When you're enforced to use an specific version of PuTTY and can't stablish the connection using WinSCP.
   
4. And when the transfer protocol is not TCP/IP.
   

I hope that @martin will soon wants to implement this.

It's not like there's some switch that you can toggle to magically make this working. Many of the necessary code is not even present in WinSCP code base.

Hi,
The last 5.20.2 beta contains the pre-release PuTTY v0.77
https://winscp.net/eng/docs/history?a=5.20.2
So, why not enable the "Shared connection feature"?

Thank you Martin for consider it!
But take note that I'm not the first to request for this.
And futhermore I suspect it will be easy to enable it. So I hope you want to almost check it internally.

Thank you for this invaluable tool.

OK. We will see, if more people ask for this.

Hi Martin,

The performance is not a problem. The question is that this could be the only solution to connect to some IoT devices. Using the "psusan" tool you could stablish a connection to a device without using a regular TCP/IP connection. In this scenario the WinSCP tool can't connect directly to these devices. But when enabling the sharing connection of PuTTY then other tools could reuse (share) the connection. That's the reason for the request.

Therefore, could you consider to add (enable) this option?
Thank you.

What would you use this for specifically? Does your server limit number of connection you can open? Imo, PuTTY terminal SSH connection is not optimized for bulk transfers. So the performance would not be optimal.

Hi,

This request it's the same as Work with PuTTY 'connection sharing' system.
But after several years the new releases of PuTTY have the option to create links (or tunnels) using other protocols different than SSH over TCP (read about psusan). And that opens a new area where has sense that WinSCP could reuse the upstream connection of a PuTTY session.

So, as the WinSCP has incrusted the source code of the PuTTY tool, then it would be interesting to enable this functionality. To configure it (internally) you only need to use the "host" and "port" and call to open a session using the "bare-ssh-connection" protocol (instead of "ssh"). Then the code of PuTTY will do the rest.

Please, could you enable this?
Thank you.