How do I know if I have a dynamic IP?
They charge extra for a Static (never changes) IP. Being a cheap bastard like me you probably have DHCP. Except for businesses most people have DHCP.
I do have an Apple base station.
It probably doesn't matter but what model.
1. First thing set up a free account at dyndns.com. Under the "Free Domain Name" choose what you want to call your domain, click Add, set up an account. You shouldn't have to check or uncheck anything except for the no spam please box, the stock options are all you need.
2. Then download a dyndns update client
. It runs in the background on a computer and notifies dyndns.com when your IP changes. What happens is when you type in yourdomain.whateveryouchose.something it goes to the dyndns servers and looks to see what your current IP address is then directs the request to your current IP address, in this case probably your home IP.
3. Next I would suggest going into the Airport Utility/Internet and under the DHCP tab, add an internal DHCP Reservation for the computer(s) you want to control. This has nothing to do with the external DHCP IP we were talking about above BTW. This step is optional as most routers hand out the same IP address to the same machines even across a reboot, but to make sure there are no changes it's a good fail-safe.
If Splashtop uses Apple's VNC software, waiting to see what Zach says on that, do the following;
4. Then you would need to open the ports for the computers that you want to control for the purpose you want. Go to Advanced then the port mapping tab. If it's Remote Desktop/Screen Sharing/VNC it is built into Airport. They use ports 3283 and 5900, UDP and TCP. 5900 is all you need to control a computer, 3283 is for the app to internally report events, you don't need that.
5. Make sure in Sharing's Screen Sharing, under Computer Settings you have a VNC password set up. Don't check mark the "anyone may request permission."