Ethernet to Cellular Modem Possible? | GSM + Ethernet + Arduino Is it possible to combine an Arduino µC with a GSM shield and an ethernet shield such that a device connected via ethernet to the Arduino has internet access over the GSM network?

I have a system with an ethernet port to connect to the internet. It works fine if I plug it into my switch at home. However, I would like this system to have its own cellular internet connection.

This is what I have found so far:


I'm basically trying to replicate the following:
https://nimbelink.com/e2clink-ethernet2cellular/#parts
If the following reddit post:
https://www.reddit.com/r/arduino/comments/3azxs6/create_gsm_cellular_ethernet_modem_with_arduino/
is any indication, I would think the answer is "no" but I am hoping to confirm from the expertise available here.
No, it's not possible.

Chiefly because the normal Ethernet shield is not capable of routing.  The Arduino never talks to the ethernet - it talks to the chip on the shield and tells it how to handle the ethernet connection - everything else is then done by the ethernet chip and the results passed back to the Arduino.

Similarly with GSM - you make requests to it and it goes off and does the work.

To link the two together you would need raw access to the incoming ethernet packets, and you would then have to perform NAT (Network Address Translation) and maintain internal state tables for current streams and such, and pass reformatted packets on to a GSM modem that could accept raw data like that.

Way outside the scope of a lowly Arduino.

Maybe possible with one of the higher end Arduino-ish systems like the Edison, Galileo or Yun (just) since they run Linux and have a real Ethernet port and a proper USB port to communicate with a proper celular modem.