3g dongles automatically connecting

Hey guys,

I’ve noticed that under resinOS2 when I connect a dongle it actually automatically connects to the mobile network, even though I haven’t touched the default network-manager config. I am currently working with Huawei e3531, but I noticed it with other dongles as well.

Is this auto-connect a function of ResinOS, networkmanager, or the dongles itself?

(FYI I’m asking because I am developing a custom board around the ComputeModule3 which is using the Huawei MU736/ME936 for internet. Would be great if it was supported ‘out of the box’ by resinos :slight_smile: )

@FransvanHoogstraten I thought it needed a Network Manager configuration file so I am not really sure what is going on here.

Can you double check there are no connection files inside /resin-state/root-overlay/etc/NetworkManager/system-connections?

@shaunmulligan might know more as he has done a lot of testing with various 3G dongles.

Hmmm, I am unable to open the folder you mention (not even on a dev image), but I’m guessing that’s the same folder as when I mount the SD card on my mac?

I’m absolutely sure there are no config files in that folder. I regularly download a brand new image from the site, burn it to SD, then immediately put dongle in and it connects…

hmmm, we updated NetworkManager recently so it may be something to do with that.

Another thing you could check is the output of nmcli c and nmcli d from the host.

Ok, will try that in a bit. I don’t have experience logging into the host-os though, I can do that with a dev image I believe right?

You should be able to log into a development device on the local network with ssh -p 22222 root@resin.local

Thanks! The outputs:

root@2d78b55:~# nmcli c
NAME                UUID                                  TYPE             DEVICE 
Wired connection 1  68672ca0-1c99-3c73-9a77-dac47e7ebaaa  802-3-ethernet   eth0   
Wired connection 2  2f044cb0-8058-300f-be47-1ef9e41027b3  802-3-ethernet   eth1   
resin-sample        bcb05b81-52cb-3828-8088-c0f55e950375  802-11-wireless  --     


root@2d78b55:~# nmcli d
DEVICE     TYPE      STATE      CONNECTION         
eth0       ethernet  connected  Wired connection 1 
eth1       ethernet  connected  Wired connection 2 
docker0    bridge    unmanaged  --                 
lo         loopback  unmanaged  --                 
resin-vpn  tun       unmanaged  --   

So the dongle shows up as eth1.

Expected behaviour? I’m guessing not :rofl: but it is working for me in quite a few production devices

Oh FYI, obviously I also had this device connected over ethernet. So ethernet + dongle.

What you see here is most likely a USB 3G dongle that is seen as a USB ethernet device. This means that the PPP connection is dialled and handled on the dongle itself, not by the host’s operating system. Most likely you configured your ISP’s details onto the dongle previously using a different computer.

This is actually quite useful and I’ll keep this in mind next time I want to put a device onto 3G.

Hmmm, can anyone confirm this? Kind of weird, because I know absolutely for sure that I didn’t configure my ISP’s details in the dongle before. The dongles I am using are fresh out of the packaging, and it is showing this behaviour with each and every brandnew dongle.

Did you buy the dongle from your provider? Maybe it came pre-configured.

Another possibility is that the dongle comes pre-configured to try and connect to the “internet” APN, as that is used by the most providers.

Which dongle are you using? I am starting to think I should go this way. ModemManager is too automatic/limited.

Hmmm, could be but unlikely, anyhow:

All my SimCards are from KPN (NL)

All my dongles are from Conrad; https://www.conrad.nl/nl/huawei-e3531i-2-3g-surfstick-216-mbits-met-microsd-kaartslot-1558341.html

They all connect automatically