Ok, well, to oversimplify things, there's an internal and external network you're dealing with. Your router has an IP address both on your network and on the internet. If you go to
this site you can see that this IP is different from the one your would see if you looked at the assigned IP address of your router. The ip from that site in the address your network is holding on the internet. The router then assigns IP addresses to the computers on it's network - but, since these are internally assigned, you couldn't access them from outside internet.
Now, there's a catch. That IP address assigned to your router from your ISP (the one you see from the website above) is usually dynamic, and changes from time to time. This makes it hard to have a reliable outside address to your network. There are free services (like DYNDNS) that will assign your a URL that always stays the same. This URL points to an IP address you assign to it. Think of it like a forwarding address. You then install a program on a computer on your network (dyn dns, for example, provides this program for free) that checks your external IP address, and sends it to service, keeping the URL and the external IP address linked when it shifts.
Alright, so now you have an address that links to your network all the time. The next step is getting a hole opened up in your network that will allow you to get from outside, through your network security, to your profilux. This is called port forwarding. You can access port forwarding by logging into your router. How this works varies a bit router to router, but basically you have it so when someone types in that external address with a port, like
http://82.145.43.12:99 (assuming 82.145... is your IP address and 99 is the port), you would forward it to port 80 on the INTERNAL IP address (such as 192.168.0.50, if that were your proflix IP address) to access the web server.) The free DNS service would replace that external IP address with a URL you chose, such as
http://blah.blah.com:99 and would eliminate the need of you trying to keep up with the shifting external IP.
Hopefully this isn't hijacking the thread too much - and sorry if I simplified it too much or not enough, but I can try answer any follow on questions!