Tag Archives: linux

ethernet over 3G/GPRS

As weird as it sounds, it is exactly that, ethernet bridge over 3G/GPRS. If you want to make your own, you will need: two machines running Linux, each with one ethernet interface and one 3G/GPRS interface, OpenVPN and a little of configuration.
First, create tap interfaces on each end (check OpenVPN docs on how to do that)…
Then bridge those with ethernet interfaces…
Now bring up your 3G (in fact, it is even easier if you have fixed connection on one end as OpenVPN server needs fixed IP)…
Next, configure OpenVPN over your tap interfaces without IP addresses and/or routing…
Start OpenVPN and see how everything coming in on ethernet interface of one of your linux boxes is going out on another and vice versa.
As for me, I used two Teltonika RUT-104 devices, slightly improved OpenWRT and SIM with fixed IP on one end. Of course, if you can not get SIM with static public IP, you can use DDNS and dynamic IP, but it still has to be public and of course, as mentioned above, server end of business does not have to be on 3G at all, it can be anywhere on internets and even behind NAT, as long as you can forward OpenVPN traffic to it.