During the summer we moved from an apartment to a house. Among many other things, this meant changes to the Internet connectivity. Our old place had VDSL, but now I got to choose what I want. Fiber optics would’ve been an option (fast and reliable), but it’s rather expensive compared to the other alternatives. In the end, I ended up with a 50/50 Mbit/s 4G mobile broadband connection which is shared through a 4G router (which I already owned). This was by far the most bang for the buck. We also happen to live quite near a 4G base station, so regular speeds reach about 40Mbit/s+. Not bad. Not bad at all. I’m not a gamer either, so no need for low ping times. On the negative side, all Finnish 4G mobile broadband connections are NAT:ed on the ISP side (exception is enterprise/business subscribers). This dilemma is also the subject of this post, in other words how to “bypass” dual NAT using TeamViewer. (I had to ditch my fancy old VPN stuff 😦 )
Well, moving along to the subject, TeamViewer. TeamViewer is by no means a new technology, but the possibility to use it on the RPi is limited. When googling you’ll most certainly find a solution named ExaGear Desktop. ExaGear Desktop enables x86 programs to be run (or “emulated”) on the RPi. While this is a good idea, it’ll most certainly be slow. A RPi running Raspbian is already quite slow, so doing x86 emulation on top of that is even slower. You’ll also find people telling you it’s impossible to run TeamViewer on the RPi altogether (which is untrue).
Why would you need TeamViewer on the RPi you ask? Isn’t there already SSH and port forwarding and such? Yes, BUT port forwarding won’t work with (double) NAT:ed 3G/4G connections. (NAT at the ISP level and NAT behind the router). As stated before, my main Internet connection at home is a 4G mobile broadband connection (without a public IP) connected to a 4G router. This combination doesn’t allow me to remote connect to my LAN using the “normal methods” (VPN, port forwarding and so on). The reason for this is that you can’t configure the ISP NAT rules (obviously). Some similar information about this dilemma can be found here for example:
https://elisa.fi/asiakaspalvelu/aihe/mobiililaajakaista/ohje/ip-osoitteet/ (in Finnish)
Luckily there’s a solution to this dilemma (and luckily I’m here to minimize your googling):
The TeamViewer IoT contest: https://www.teamviewer.com/iotcontest 🙂
Just download and install it in Raspbian (with a simple double click). After that have a look at the Frequently Asked Questions and the General Questions & Answers + Troubleshooting Questions and Answers on the same download page. The only settings I changed were:
Sat an unattended fixed password and disabled random password (via the GUI).
Edited /boot/config.txt and commented out framebuffer_width and framebuffer_height lines. I left them at 1280×720 which worked OK for me. (I did this because I’m running the RPi headless and the resolution would therefore be screwed up (too tiny) if connecting without a monitor attached to the RPi).
Added the RPi to the “My Computers”-list in the TeamViewer client (from Windows)
…and some screenshots:
Fig 1. Connected, yey 🙂
Fig 2. Having a look at the doggycam remotely
Pay a slightly more expensive monthly fee for your mobile broadband connection, and in return get a public IP address. This is true for almost all ISP’s here in Finland at least.
Some ISP’s provide public IP’s on 4G mobile broadband connections using IPv6. This only works with a couple of mobile broadband sticks/routers however (they have to fully support IPv6). I wouldn’t buy a new stick (or router) only for this feature. (They’re rather expensive after all).
Use TeamViewer on a x86 computer instead of a RPi. Yes, why not. Then again it consumes much more energy than a RPi when in use 24/7. It’s also noisy. And hey, everything is always much more cool and hip with a RPi 🙂
That’s it! This was just a short little post that hopefully will make your life a whole lot easier when dealing with the evil NAT:ed 4G connections 🙂