Once you go cellular, you are on the external internet so there are a couple of extra things to check:
• FMPA peer-to-peer server uses port 5003. Make sure that it is open (no firewall) and forwarded from your router if you are using one.
• Use the server's internet IP address (http://whatismyipaddress.com) in FM Go to connect to the remote database not the server's LAN address on your WiFi network. Since your ISP or router may change your designated internet IP address, it's better to setup a static IP address.
That was a complete disaster. I tried setting up a static IP and port forwarding on my AirPort Extreme wirelessly connected iMac running Mavericks. I thought I was following the guidance of the sites provided above fairly well. I subsequently lost all Internet connectivity. I ended up having to do a hard factory default reset of my AirPort and deleting my my SystemConfiguration folder and rebooting my iMac to get connectivity again. All told...4 hours of wasted time. I obviously need better guidance! LOL
Oh yes...when I called Comcast to see if they would help me with my settings without having to reset everything...they tell me that there's an extra charge for a static IP address (I didn't explain the type of static address very well), note that I was trying to set one up in my account and then tell me I need to call Apple to have them fix my screw up.
Static IP addresses stay the same until you quit paying for them.
Dynamic IP Addresses MAY change after a prolonged power outage, or if you replace your IPS's Modem|Router.
It is not necessary to have a static IP address, just be aware that it might change.
There are sites (have not been to one recently) that get around the Static | Dynamic possible problems.