I'm not very networking-wise, got a question: is the "local machine" alwyas a well-defined thing? I'm thinking about stuff like where hosts are transparently distributed. Maybe there are systems out there that take advantage of resolving localhost to other than 127.* in order to make applications easy to transparently migrate when scaling servers out, or something?
If we are running distributed services, we know the machine that the code is run on is running. We can even reference this by many languages version of "this" keyword.