I'm not saying it cannot be done, but it certainly won't be easy.  Since the AD authentication module works by authenticating to your domain, if your server is not part of the domain it won't work as expected.    I'm sure it "could" be done, but you would have to be an expert in Windows Authentication to get it to work properly (and safely).  Honestly, your best bet is to put that server on the Domain, and then it gets really-really simple to do this.

You could use one of the other Authentication Providers to do Authentication, and there might be a third-party module that will do it also, but I wouldn't recommend trying this one.