OpenWrt firewall blocks almost everything against the WAN for security
Look for allow WAN web OpenWrt if you want to access the router over the WAN,
Allow WAN ping
Allow WAN ssh
You can’t access what’s behind a router over the WAN, just like you can’t access your home LAN over the internet.
You will have to make a VPN or you can open ports against a local network IP. But it will only work against a PC on your Xiaomi LAN through the router’s WAN IP
Edit, okay I’m trying to make you see both and what you want is for them not to be seen.
Declare two LANs on the opwrt router and you’re done.
If eth1 is the WAN
Create eth0.3 for the second LAN
You will have two LAN networks with two DHCP all going out through a single WAN and they will not see each other but you will have internet
Login to Luci web interface.
A. Create New VLAN3.
Click Network → Switch then click “Add” button to create new vlan3 as shown in the picture ports 3 and 4 are untagged and CPU is tagged.
Click the “Save and Apply” button.
B. Create a new Interface (lan2).
Click Network → Interfaces Click “Add new interface” button.
Set the “Name of new interface:” to lan2
Set the “Cover the following interface” to eth0.3
Leave the “Protocol of the new interface” to its default setting “Static address” the click the “submit” button.
LAN2 will be created as a new interface click the edit button.
Set the following fields.
IPv4 Address: 192.168.22.1
IPv4 netmask: 255.255.255.0
IPv4 gateway: 192.168.22.1
Use custom DNS servers: Leave this blank
Note: Please Do not use DNS server unreachable from lan2 interface.
C. Create a new Firewall zone.
Click Network → Firewall click “Add” button under Zones.
Set the following in the “General Settings” Tab.
Name: lan2
Input: Accept
Output: Accept
Forward: Accept
Covered Networks: select “lan2”
Inter-Zone Forwarding
Allow forward to destination zone: select “WAN wan6”
Click “Apply & Save” button.
That’s it and you are done