Is This Checker Safe to Use?

YES! No information is ever stored, therefore anything you submit is never remembered.

I See My IP Address, Why?

This application gets your public IP Address. This is the address that servers read when you establish a connection with them. Your IP Address is shown in the event you do not know your address, and are attempting to grab that when port forwarding or checking open ports from servers you host. This information is never stored and no one BUT you can see this.

How Exactly Does This Application Check if a Port Is Open?

When you run a server, sockets are opened for connections. This application attempts to connect to the server on the port supplied by tunneling through the socket and establishing a connection to the server. If a connection can be established, it registers as open. If no connection is established, it registers as closed.

Making something like this is fairly easy, however I did this the hard way, to make it easy for those who aren't skilled in programming. PHP has a built in function: fsockopen(). This is used in the connection and testing, but a huge portion is of my own.