There is an issue with parsing an IPv6 address on the command line if a tunnel is used at the same time. It does work within a normal WinSCP-stored-sesssion, but it doesn't work using the /rawsettings switch for the tunnel. After the connection dialog is shown, it stops with an error message "Network error: Connection to 127.0.0.1 refused".
Tested on Win7 / Win10
I used the following command line:
WinSCP.exe sftp://<user>:<pwd>@[<IPv6-address>] /rawsettings Tunnel=1 TunnelHostName=<IPv4-Address> TunnelUserName=<user> TunnelPasswordPlain=<pwd>
I've a linux VM which has an IPv4 and IPv6 address. It's easily reproducible this way. Attached are two debug-logfiles. One does show how the connection is failing if it is started via command line, and the second logfile is the same connection-setup just as a stored session (which is working correctly).
If more details are needed, just let me know.
Thanks in advance.