You’ve certainly heard the word “server.” It’s a type of computer that generally provides or manages services. For example, this website is hosted on a web server, a computer running specific software that can respond to browser requests and send web pages to users anywhere on the internet. You send email through a mail server, a computer with software that routes email to and from your account. And a file server is a computer set up as a receptacle for files, so other users can connect to it and copy files to and from it.
A server is nothing more than a standard computer; what differentiates it from a “client” computer–such as the one you’re working on–is its software and its ability to receive and process connections and requests.
You may not realize it, but your Mac is a server too. It contains all the software you need to host websites, manage email, serve files, and much more. All you need to do is turn on these “services.” Apple makes this really easy; you can buy the OS X Server app (for $20) from the Mac App Store, and tweak a few settings, and then turn your Mac into a server in minutes.
Read the rest of the article on The Mac Security Blog.