When people lived in small towns and everybody knew everybody else, there was no need to lock your doors. You knew all of your neighbors by name. Everybody looked out for everybody else, and everybody knew everybody else's business. Trust was the order of the day. Life was good.
But as the town grew, people moved in and out more often, and it was too hard to keep track of your neighbors. Strangers lived among you, and trust was no longer the order of the day. Security was the order of the day. Welcome to life in the big city.
The i5 is a lot like a small town, growing into a big city. As a small town, you know everybody that is connected to your machine. As a big city, connected to the Internet, strangers live among you. You must take precautions.
The point is this: If you connect your i5 to the world, you must change the way you think and act about security. Most of the people who use the Internet have good intentions, but it only takes one cracker (a hacker with malicious intent) to ruin your day and maybe your business.
You must think about whom you are going to let onto the system and what they can do when they get there. Ask yourself: How do we prevent the user from doing anything other than what we will allow? Are there any "back doors" through which the user can execute programs that you didn't intend to make available?
In your current environment, you probably are not using all the built-in security features of the server. If you live in a small town, why would you need to? But now that you are connecting to the Internet, you must make sure that you implement all the security features you already have.