Port 587 is the `submission' port. It sounds like your Postfix isn't
listening on that...
You're right, That's it in a nutshell. I confess that I didn't
even consider the possibility that nmh would be using 587 rather
than 25... although it is certainly more correct for it to use
587 when submitting.
You know, you're not the first person to have been bitten by this. It
occurs to me that we should print the port number that we are using in
the error message, as that would provide a hint to people as to what is