Wi-Fi Bridge

[DRAFT - hmm, it seems like several steps, references and troubleshooting have all been deleted. History doesn't go back long enough to show when this happened. The steps stop with wifi being turned off - perhaps, this should read turn off MacBook's wi-fi???. https://pimylifeup.com/raspberry-pi-wifi-bridge/. I need to check if this guide works as it is]

A Wi-Fi bridge allows a device that only has an ethernet port to access the net using Wi-Fi.

For this project, I'll use a Raspberry Pi 3B+ running raspbian stretch

Parts:

Raspberry Pi 3 B+, Amazon/Element14, $37.78

microSD Card (5 pack only need one), Amazon, $22.75

Miuzei Case, Power Supply, Fan and Heat Sinks, Amazon, $16.59

Ethernet cable, Amazon, $5.48

Step 1. Setup Raspberry Pi 3 B+ with Raspbian

In Step 1 instructions use the optional step, to set up the Raspberry Pi as Headless.

When complete, you should have a username, password, and hostname with a Raspberry Pi connected to your Wi-Fi network

Step 2. Update and Upgrade

Open a terminal window on the MacBook

Run the commands:

$ ssh pi@hostname.local

$ sudo apt-get update

$ sudo apt-get upgrade -y

Step 3. Add Simple Fan

To check the temperature, run the command

$ vcgencmd measure_temp

In general, the fan should not run. If it is running all the time, then something is wrong.

Step 4. Install dnsmasq

In most setups, the Raspberry Pi only has the Wi-Fi or the ethernet interface active. For a bridge, we need to connect a device using an ethernet connection, and then traffic must flow over the Wi-Fi interface to get to the home LAN and out to the internet.

By having traffic flow from a device with only an ethernet connection, through the Raspberry Pi, and out over Wi-Fi to the internet the Raspberry Pi will have to act as a minimal router.

The first step is to get dnsmasq installed using the command:

$ sudo apt-get install dnsmasq -y

Step 5. Set up Raspberry Pi ethernet port

$ sudo nano /etc/dhcpcd.conf

# wi-fi bridge

interface eth0

static ip_address=192.168.220.1/24

static routers=192.168.220.0

Step 6. Set up DNS and DHCP

Create a backup of the dnsmasq.conf file

$ sudo cp /etc/dnsmasq.conf /etc/dnsmasq.backup

Edit the conf to contain the following lines:

$ sudo nano /etc/dnsmasq.conf

interface=eth0 # Use interface eth0

listen-address=192.168.220.1 # Specify the address to listen on

server=8.8.8.8 # Use Google DNS

domain-needed # Don't forward short names

bogus-priv # Drop the non-routed address spaces.

dhcp-range=192.168.220.50,192.168.220.150,12h # IP range and lease time

Step 7. Enable IPv4 forwarding

Enable IPv4 forwarding

$ sudo nano /etc/sysctl.conf

Uncomment this line

net.ipv4.ip_forward=1

Step 8. Restart services and Raspberry Pi

$ sudo service dhcpcd restart

$ sudo service dnsmasq start

$ sudo reboot

Step 9. connect MacBook to raspberry pi

Turn off Wi-Fi and plug MacBook into Raspberry Pi using an ethernet cable.