I have device A and B. I need them networked together (see eachother on arp-scans etc). Device B has WiFi, but device A has Ethernet. Basically I just want the Pi to act like a simple router (maybe this isn't the right term) for an internal network.
How can I configure the Pi to host a WiFi network over wlan0 (hostapd + dnsmasq I guess) but also allow a client to connect via Ethernet in the same way a client connects over WiFi (including DHCP)?
I've already had it almost working, but the Ethernet client was under 192.168.2.X while the WiFi clients were on 192.168.1.X. They could access each other by IP address, but were still on separate networks, which isn't what I want.
Below is a diagram of what I want: