If you already have FileMaker Server 12 up and running and already have FileMaker Pro 12 clients connecting to it in one form or another then you should not have to do anything special to get FileMaker Go 12 clients to connect to those files also.
Yes...the iPad would need to connect to your hosted file by way of Wifi or 3G if your iPad is so equipped. If you do not have a Wifi network as part of your overall network configuration you would need some form of wireless router. But if you are using your iPad for email and surfing the web then you likely already have Wifi setup and ready to go.
In the end, connecting to a hosted file with a laptop using FileMaker Pro and using an iOS device and FileMaker Go are no different.
Thanks Steve for your answer.
The ipad is equipped wifi. and Mac pro is equipped wifi too..
the Mac pro is sit in intranet.
and ipad only has internet access, not be able to access to intranet due to security issue. that means I have to create my own private WIFI network in order to get access to filemaker files on the MAc pro from ipad via wifi. I truned on Mac pro wifi and create wifi network give a name. and I truned on ipad wifi , I can see the network , so I chose the network. opened filemaker GO, Ipad can search mac pro's WIFI ip address , however when i put file name to open, it says file could not be opened. Either the host is not available, or the file is not avaiilable on the host. I have no problem to access hosted file from desk top which is in the same network.
... in support of Steve Romig's post....
You may need to open the port 5003 on the router and port-forward to your Mac Pro if the iPad only has internet access.
If the Mac Pro is only on the intranet... how is it being hosted to the other desktops? Are you using wifi? If so you will need to configure the wifi on your ipad to use the same network.
If you have no router, you should be able to set up an Apple wireless base station or turn on the wifi on the MacPro and allow the iPad to connect to that.
We probably need a clearer picture of your network and capablilities to make any more specific recomendations.
with my ipad on WIFI can access my fields to my computer, but remote i can not access my files? why
Most likely, your computer does not have public address that can be looked up through DNS. So you can't get to it from the internet. There are services like dyndns.org that will track a dynamic address and give you a domain name that will let you access the computer for. The outside.