As part of the Cygwin SSH Server setup, there’s a step that prompts you to enter a value for CYGWIN, aka the CYGWIN environment variable. Actually that last part is not really correct. It’s not an “environment variable” in the strict Windows sense – manageable via the Windows Advanced Systems Settings applet. What it is is a little-e environment variable that is used when the SSHD service starts.
I used some old documentation that asserted that the correct value for this item was ntsec bin tty, but ran into the following when I sshed in to the server from a remote client:
So TTY is no longer supported. Duh – the official docs show that TTY is obsolete.
So how to change it?
It turns out that there is no configuration file in your Cygwin install directory that stores this information. It’s in the Windows Registry, in a few places:
Without digging too deeply, I’m guessing that those last two are implied from the first – but I went ahead and changed them all, just to be safe. Then I restarted the SSHD service and voila! No more TTY nag message upon SSH login.