It is not using any port so far...
offtopic:
What is the big deal about using just one port anyway?
Compatibility
Thats the deal with it.
Normally programs have say a default port, then ports you can route it through.
Its because anyone with any knowledge of how the internet works n' stuff knows that boosts your security on your machine quite a bit, as computer viruses usually use the same ports over and over. Its also because if a very popular program, lets say "Internet Explorer" (excluding the fact theres better browsers, and ports are more complex then that), used 1 port, and only ever 1 port, and the same port for everyone every time, If someone wanted to make a virus or malicious program which fed back information to its creator, or allowed remote control of a machine, they could use the internet explorer port, and have a good chance that any computer they infect has that port open.
In reality ports, connections, packets and security is far more complex. But as a simple model, thats kind of why...
Alternatively it may be commercial products allowing port changing, to aid in internet traffic management, as X, Y and Z ports could be for the browser on their computers, they don't need to check every port when they know a virus was downloaded via the browser, to find the instance of the virus downloading, or it makes it easier to track people going on things they shouldn't be using the workplaces computers.