RPI 4 tethering DNS problem

1st Official Post

    Hi. *disclaimer* I have seen several "similar" threads around, but since I'm not sure the problem is actually the same, I open a dedicated thread. Do not hesitate to merge if you think this is relevant.

    Setup :

    I have Libreelec 9.2.6 installed on a raspberry Pi 4. It is connected via ethernet to my modem/router. Everything works fine.

    Since this router has terrible wifi, wifi is simply not activated on it. So the plan is to use Libreelec tethering tho get a wifi AP.

    Problem :

    When tethering is activated, I get no Domain Name resolution after reboot. The Pi (and connected devices via wifi) can ping an IP, but no domain. Kodi addons do not work anymore (can't resolve domain names I assume).

    Details :

    Pi's IP is 192.168.0.14 (note : same result whith DHCP or fixed IP)

    My modem/router/gateway ip is 192.168.0.1

    My internet provider's DNS are 89.2.0.1 and 89.2.0.2 (note : same result with google's DNS)

    When wifi is simply activated, no problem.

    When I activate Tethering (without rebooting) here is what I get :

    Code
    Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.0.1     0.0.0.0         UG    0      0        0 eth0
89.2.0.1        192.168.0.1     255.255.255.255 UGH   0      0        0 eth0
89.2.0.2        192.168.0.1     255.255.255.255 UGH   0      0        0 eth0
192.168.0.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
192.168.0.1     0.0.0.0         255.255.255.255 UH    0      0        0 eth0
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 tether

    Everything is working fine, kodi addons work, I can ping Domain names, connected devices via wifi can navigate the web.

    However, here is what I get after reboot :

    Code
    Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.0.1     0.0.0.0         UG    0      0        0 eth0
89.2.0.1        0.0.0.0         255.255.255.255 UH    0      0        0 eth0
89.2.0.2        0.0.0.0         255.255.255.255 UH    0      0        0 eth0
192.168.0.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
192.168.0.1     0.0.0.0         255.255.255.255 UH    0      0        0 eth0
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 tether

    Can not ping domain names anymore (pi or connected devices), addons not working, can ping an ip.

    So, if I understand this properly, after reboot, I get an incorrect gateway for the DNS.

    Anyone with a solution would me my personal hero for the week end. :angel:

    (I did quite a lot of reading about connman, connman's dns proxy and ip forwarding this morning, but it's all getting a bit mixed up in my poor brains, and I would like to avoid messing up my all system with bold experimentations. ^_^)

    And thank you for this beautiful distro, BTW.

    • Official Post

    First thing to do is retest with a current LE10 nightly to validate the problem still exists, because basically everything in the OS is updated (including connman) and there will be no more 9.2 releses. FYI, LE does not use the DNS proxy feature in connman.

    Crash-tresting then ?

    Fair enough (on some new SD card, though... ^_^)

    However, I might be thick, but I can't seem to find any nighlty for LE 10. The ones I can find here : Index of / seem to be 9.8 only.

    Have I missed a repo ?

    OK, thx. Done. I've lost my custom skin and a bunch of addons, but nightly launches and behaves decently.

    However, same result exactly. When tethering is activated from the UI, everything is fine, but once rebooted :

    Code
    Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.0.1     0.0.0.0         UG    0      0        0 eth0
89.2.0.1        0.0.0.0         255.255.255.255 UH    0      0        0 eth0
89.2.0.2        0.0.0.0         255.255.255.255 UH    0      0        0 eth0
192.168.0.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
192.168.0.1     0.0.0.0         255.255.255.255 UH    0      0        0 eth0
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 tether

    and of course, can't ping anything by domain. :(