Cannot sync remotely (but can sync locally)

[mvoogt]

I have MirrorSync installed on my 10.10.1 OSX server running Filemaker Server 13.0.5.520

 

I can sync to the server from Filemaker Pro Client while on the network however as soon as I take the spoke database outside the network, the MirrorSync script on the spoke can no longer see the remote server. I get an error message that references trying to type the URL http://servername/MirrorSync/sync

 

That page does not load remotely (it does using the local IP inside the network).

 

Port 5003 is open on the router (Apple Airport Extreme) connected to a Netgear 6200 Modem in bridge mode (PPPOE on the router). ISP is AT&T.

 

I am able to connect remotely to the server database in the traditional sense (as port 5003 is open).

 

Let me know if you need any other details.