I'm searching for a small SMTP relay for Windows which can transparently translate SMTP from a dumb client and does authenticated SMTP and STARTTLS to the server. In essence, something like SMTPAuth which I've used for a couple of years and just works. Unfortunately it is lacking on the TLS bit. Ideally it'd be a Windows service (or at least could be set up with srvany) and doesn't have to otherwise be fancy. Any ideas?