DHCP client - no address asigned: WIFI internet, router no


so I have the following problem: I have a USB LTE dongle installed on an old raspberry pi 1 that forwards the connection via LAN to my router. I used to have the dongle plugged in directly to the router but it crashed all the time and with the raspberry, in the middle, it works completely fine without crashes.

So, but here is where the problem arises:

I used to have the USB dongle installed and created an interface that acted as a DHCP client and received the internet from the dongle. IP address assigned and everything. I could use the DHCP server of the router and everything worked fine (except the crashes).

Now with the raspberry in the middle, I put the connection also in DHCP client mode and am receiving the connection via LAN from the raspberry. Here is where strange things happen:

  • The eth0.1 switch (connection on eth0) does not receive an IP address from the dongle
  • Eth0.1 is receiving and sending packets
  • The bridge from eth0.1 to the WIFI works fine... the internet is working fine on all clients
  • Except that the router itself has no internet connection and can't connect to the IP address of the dongle
  • All clients receive IP addresses given to them from the dongle instead of the router
  • The router is not reachable; only when I manually put in the IP address, netmask and gateway IP it is reachable again (but without internet access)

As I said before with the USB dongle directly plugged into the router it connected fine, the router was handling everything. Now with the raspberry in the middle and connected via LAN all WIFI clients get the dongle DHCP forced upon them, working with the router DHCP doesn't work and the router itself has no internet connection although everyone on WIFI has internet.

What is happening? Can anybody help me? Thank you!

Firmware: OpenWRT version 18.06.4 r7808-ef686b7292 (kernel: 4.9.184)
Router: TD-W8970 xRX200 rev 1.2.
Raspberry Pi 1 model b
USB Dongle: ZTE MF833V

  • What's the IP of the dongle or the network you're connecting it to?
  • By chance, does that IP range match the OpenWrt LAN?

The IP of the dongle is (range: 100-110) and the openwrt router has (range 200-255). I'm doing the tethering of the dongle via the raspberry with connman (ethernet tethering). I'm not sure if that may be might cause the problem.