Thanks for the help with this. My colleague and I are trying to setup a RPI 4 as a router not connected to the internet. It is just for the purposes of connecting multiple wifi controllers together. The controllers are wifi but the main computer we want to control them with would be plugged into the ethernet port. The problem is all the examples online NAT and we can't figure out how to make the ethernet port just another DHCP addressable interface to the router.
To date the closest recipe we have used is below. It makes routing over the wifi great but we can't talk to anything through the ethernet port.
sudo systemctl unmask hostapd.service Sudo systemctl enable hostapd.service Sudo vim /etc/dhcpcd.conf Go to the bottom and add the following Interface wlan0 static ip_address=10.20.1.1/24 nohook wpa_supplicant Sudo vim /etc/sysctl.d/routed-ap.conf Add the following net.ipv4.ip_forward=1 Then run sysctl -p Sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE Sudo rm /etc/dnsmasq.conf Sudo vim /etc/dnsmasq.conf Add the following interface=wlan0 interface=eth0 dhcp-range=10.20.1.100,10.20.1.200,255.255.255.0,365d domain=wlan address=/rt.wlan/10.20.1.1 Sudo vim /etc/hostapd/hostapd.conf Write the following country_code=US interface=wlan0 ssid=switchblade_SN# hw_mode=g channel=7 macaddr_acl=0 auth_algs=1 ignore_broadcast_ssid=0 wpa=2 wpa_passphrase=switchblade123 wpa_key_mgmt=WPA-PSK wpa_pairwise=TKIP rsn_pairwise=CCMP
Needless to say this isn't the only way we have tried. Mostly we have monkeyed with the iptables and the dnsmasq.conf. Pretty much we are just trying to find a way to do LAN/Wifi without internet access. Any help would be appreciated.