Let me introduce to the situation we had to face it and the core of the question.
We needed in our project to change the "localhost" to be something else like "newdomain-localhost.com", so we changed the hosts file (in Windows) and everything worked.
We reached the wall of Facebook with its sharer, where you need to get the site into a whitelist if you want to share content like flash. It's allright with the production server, but what happens in the dev enviroment?
My question is: if I change the hosts file to get localhost into something like "newdomain-localhost.com", when a request is thrown from my local machine to a service like Facebook, Facebook will take the domain "newdomain-localhost.com" or directly the public IP of my machine (which in this case is fixed, but it can be dynamic)?
Let me add that I think it perfectly makes sense to say that the hosts is something that affects locally, and the service receives the public IP instead of the domain name.
Correct?