Wifi Hotspot with OpenWRT

How to create a transparent Wifi Hotspot using OpenWRT

Using for example an old TP-Link 781 that doesn't have enough memory to install the web graphic (Luci) interface : that why after a reset (push the reset button for 10 second while the router is on), http://192.168.1.1 give a "connexion refused". It's possible to activate the wifi hotspot "OpenWrt" with the Wifi ON / OFF Button

And later,

 opkg install luci

will fail with various problem (out of memory for example)

So we have to configure it threw ssh, to access it :

  ssh -o HostKeyAlgorithms=+ssh-rsa root@192.168.1.1

There is no root password after a reset

Then we would like to configure it as a transparent router : it won't give an IP to the LAN, the IPS Box will take care of that, to do it, follow this configuration https://openwrt.org/docs/guide-user/network/wifi/bridgedap

Disabling dnsmasq disable DHCP on the lan ports

It worked and again lost many packets, so Switch to trash !