When ESP32 module connects to Wireless and Ethernet which connection takes priority?

[Jibun-no-Kage]

When ESP32 module connects to Wireless, i.e. network.WLAN and Ethernet, i.e. network.LAN which connection takes priority, or in other words which interface is the default route? I don't any module method to set the metric of each connection. Is it last connection creating that owns the route? So if I create wireless object then Ethernet object, Ethernet owns default route?

[sosi-deadeye]

I was testing the ESP32-S3-ETH-8DI-8RO-C with Micropython. This device has an integrated Ethernet Port (W5500) and Wi-Fi support. I was connected via Wi-Fi and Ethernet together.

The router assigned 192.168.0.99 via Wi-Fi and 192.168.0.102 via Ethernet.
So created a socket to listen on "0.0.0.0" or "" and were able to use both interfaces.

The socket module has also SO_BINDTODEVICE, but this does not work with LwIP AFAIK. They do not have internal names like eth0 or wlan0. If you look in LwIP, you won't find SO_BINDTODEVICE in LwIP. I guess it's used for the Unix-Port.

If you want to listen only on one interface, then use the source-ip to bind, otherwise use "0.0.0.0" or "" as IP to bind.