Hi,
I tried smartphone Tethering as I will switch providers soon and during that I'd like to use the Android smartphone during the switch-over process (which would disconnect the main line). However this doesn't work.
mySetup
openwrt router connected to DSL router (modem+router). eth0 is in subnet 192.168.0.1/24 just like the router. Its not double-NATted but there is a static route setup in the DSL router. (BR-LAN is 192.168.1.1/24) Behind openwrt are the devices (connected via BR-LAN). openwrt acts as router only, no dhcp no dns (there is another dhcp/dns in the lan)
I used the wiki page (https://openwrt.org/docs/guide-user/network/wan/smartphone.usb.tethering) and installed the kmod-usb-net-rndis on the openwrt (fritzbox 4040 with openwrt 21.02). The smartphone itself is recognized and I get an IP adress from its dhcp server on the hw interface usb0. Also if I disconnect my mainline (changing the device to usb0 on the WAN interface) I can hop on via ssh to the openwrt from a client and run there "ping google" and it resolves the adress and icmp works to the google servers. But when i try from client (that is in subnet of openwrt router br-lan) I can't even ping 8.8.8.8
I know that the smartphone tethering works also if attached to other clients directly, it seems to be something on the openwrt not forwarding the packets?
I remember in the past i managed to get it working, however i believe i had a routed phone back in the day and fiddled with the routes in the phone, but its too long ago (i think i did some route add commands)
Do I also need to add a forwarding on the smartphone like i had to do on the dsl router? How would I even do that on an unrooted phone? Or do I need to put my clients in the same subnet as the opnwrt usb0 interface is in?
Thanks for helping me out