Ethernet switch working, but not Internet switch

Greetings:

This comes with the official preface that I am a novice with all aspects of Arduino, including networks, so please excuse any basic errors on my part. So, I am completely determined to get my Arduino connected to the Internet, for purposes of data logging and controlling devices remotely. I am starting with this set of Instructables on Ethernet switching: http://www.instructables.com/id/Ethernet-Switching-with-Arduino/

Right now, I am working with the following hardware:

-Uno Mega2560
-Seeed Studio Ethernet shield (Wiznet 5100)

So far, I have everything working, and I can control the LED's from my ethernet. However, once I leave my home network (e.g., using 3g instead of wi-fi on my phone), I cannot control the device. I'm guessing it has something to do with either the IP or the gateway addresses, but I don't know enough about networks to begin to debug this problem. Any suggestions?

BTW, I have my Ethernet shield tied directly into my router. My computer that I am using to get everything configured is a Mac.

Thanks in advance.

Brian

To connect from out on the internet you will probably need a dynamic IP service like no-ip.com for an address like brian.no-ip.com and set the port fowarding on your router to foward request your ethernet shield.