www.ipchicken.com will give you your public ip address for your router. You will have to setup porting forwarding on your router to your local server ip address. Your router manual will have information for settting up port forward on your router.
When you enable iwp you specify a port. The default is 80 filemaker recommends port 591. If you use 591 you will have to append :591 to the end of the web address. such as 192.168.1.10:591
You will have to open port 5003 also.
You need to open ('port-forward') port 591 is you want to access the file using a web browser. You need to open port 5003 if you want to access using an FM Client.
thanks for getting back to me,
I have talked with my systems administrator and it seems that we are in a very secure area and its unlikely that they will let us open a port. Do you know of any other way to achieve access over the web?
I could look into drop box etc but I believe that could end up causing damage to the database.
Drop box is not a viable option. If you cannot open a port, your options for accessing your database from a remote location are extremely limited. You might see if VPN (virtual private network) or RDP (remote desktop) might serve for what you need to do.
If you use a VPN you will be able to access the file either way (FM Client, or IWP if you know the internal IP address). I would be interested to hear what they feel are the security risks of a correctly-opened port. (Obviously any access to the files is only as secure as the username and password.) It is always easy to 'Just say no'.