How to expose IOT devices control to main network over WIFI Nat range extender

Hello Openhabianers,
I need your help for scale up my domotic system.
I made by myself an ESP8266 wifi range extender with a few of cents by installing Martin-ger firmware

My objective is extend the wifi covering where is not reachable by the main router signal and to do all the fantastic stuff we usually do with our Sonoff, Sensors etc etc… BUT i have some trubles =(
At the moment I’m not able to comunicate between the subnet created by the wifi nat extender and I cant undestand how to do.

Here my datas:
Router IP = 192.168.178.1
Range extender IP on the main router = 192.168.178.106

AP subnet (inside range ext. config) set as default = 192.168.4.0

sending telnet command “show dhcp” output is

cc:50:e3:5d:1b:f4 - 192.168.4.2 - 68
48:db:50:2f:c4:48 - 192.168.4.3 - 68

(I think is the two sensors connected to the nat router right?)

sending telnet command “show route” output is

Network              Dest
192.168.4.0/24       ew1
192.168.178.0/24     ew0
127.0.0.0/8          lo0
default              192.168.178.1

main router is a frizbox 4020 and I can manage port forwarding if i can understand needed parameters to set

what I have to set to be able to ping and send commands to the domotic sensors connected on the range extender ???

Thanks in advance for your help.

you can’t comunicate between different subnets by default. That’s what VLAN’s are for and you have to have router which is capable of routing between VLAN’s

so you create mainnet eg. VLAN1 and subnet aka VLAN2 and on the router you’ll specify routing between those two.

Even if Http traffic is unable to reach router. Is important to know that MQTT messages are correctly received from broker between the two networks.

cheers