Bridge 5Ghz to ethernet (2.4Ghz Only products that need to be on the network)

[branx86]

Setup Instructions
1.    Connect the Hardware:
o    Connect your Raspberry Pi 4 to your home's 5 GHz Wi-Fi network.
o    Plug a standard Ethernet cable into the built-in Ethernet port (eth0) on the Pi 4.
o    Connect the other end of that cable to a USB-to-Ethernet adapter.
o    Plug that USB adapter directly into an open USB host port on the Snapmaker U1 controller box. [1, 2, 3]
2.    Configure the Pi Bridge Software:
o    Open the Raspberry Pi terminal.
o    Install the network bridging tools: sudo apt install bridge-utils
o    To automatically forward all incoming 5 GHz traffic from wlan0 straight to the Ethernet port eth0, activate IP forwarding by editing the sysctl file:

Bash:
sudo sysctl -w net.ipv4.ip_forward=1

Configure an IP masquerade ruleset using iptables to share the connection:
bash
sudo iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE
sudo iptables -A FORWARD -i wlan0 -o eth0 -m state --state RELATED,ESTABLISHED -j ACCEPT
sudo iptables -A FORWARD -i eth0 -o wlan0 -j ACCEPT

3.    Verify on Snapmaker:
o    Reboot your Snapmaker U1.
o    Navigate to the touchscreen settings network panel. The printer will bypass wireless scans and automatically pull a hardwired local IP address generated by your Raspberry Pi router bridge.

Part 1: Make Firewall Routing Permanent on the Pi
By default, the iptables rules you entered are saved in active RAM and flush upon reboot. To make them persistent, you will use iptables-persistent: [1, 2]
1.    Run the installation package command:
bash
sudo apt install iptables-persistent -y

2.    During the installation, a blue configuration prompt will appear on your screen. Select Yes when it asks to save current IPv4 rules.
3.    If you ever change or update your network routing rules in the future, save over the persistent configuration manually using:

bash
4.    sudo netfilter-persistent save

CONNECTION
Router -->(5Ghz)--> Raspberry Pi 3B+,4,5 wLan0 ->eth0 ---> Ethernet cable ---> USB to Ethernet Adapter -->plugged into USB A port of the Snapmaker U1 3d Printer