To stream from MC to your iOS device when you are away from home, you will generally need to set up Port Forwarding on your home router, to forward MC's port through the firewall on the router to the computer that runs MC.
The best bet is to get streaming working first while at home (with the iOS device connected to the same network as the PC that runs MC). Only then try to set up streaming over the Internet.
How you do this is specific to your particular router and home network setup, but with typical home routers, it usually involves:
1. Setting up the computer that runs MC with
a static (unchanging) IP address on your home LAN.
2. Opening up the administrative web page served by your home router (often
https://192.168.0.1 or something like that) and logging into it with the administrative password (this is
different from your Wifi password, or very well should be).
3. Finding NAT or Port Forwarding settings in the router's admin interface, wherever they hide it.
4. Forward the port used by MC (found under
Tools > Options > Media Network > Advanced > TCP Port) from the Internet to the internal static IP address you defined in step 1 for your MC-running computer. I believe it is port 52199 by default, but check the setting in your copy of MC to be sure. If it gives you the choice, you only need to forward TCP traffic and not UDP.
5. If you have a software firewall enabled on your home PC, you may also need to set it to
allow inbound connections on the same port.
6. Set up JRemote to connect to MC using the Access Key set up in MC under
Tools > Options > Media Network.
That should do it. Advanced network setup is a bit outside of the scope of this forum. Here's a how to guide that goes into more detail:
http://www.howtogeek.com/66214/how-to-forward-ports-on-your-router/
