/esp32_nat_router

A simple NAT Router for the ESP32

Primary LanguageC

ESP32 NAT Router

This is a firmware to use the ESP32 as WiFi NAT router, based on the Console Component and the esp-idf-nat-example. It can achieve a bandwidth of more than 15mbps.

Usage

For configuration you have to use a serial console (Putty or GtkTerm with 115200 bps). Use the "set_sta" and the "set_ap" command to configure the WiFi settings. Changes are stored persistently in NVS and are applied after next restart. Use "show" to display the current config.

Enter the help command get a full list of all available commands.

If you want to enter non-ASCII or special characters you can use HTTP-style hex encoding (e.g. "My%20AccessPoint" results in a string "My AccessPoint").

Flashing the prebuild Binaries

Install esptool, go to the project directory, and enter:

esptool.py --chip esp32 --port /dev/ttyUSB0 \
--baud 115200 --before default_reset --after hard_reset write_flash \
-z --flash_mode dio --flash_freq 40m --flash_size detect \
0x1000 build/bootloader/bootloader.bin \
0x10000 build/console.bin \
0x8000 build/partitions_example.bin

As an alternative you might use Espressif's Flash Download Tools with the parameters given in the figure below (thanks to mahesh2000):

image

Building the Binaries

The following are the steps required to compile this project:

Step 1 - Setup ESP-IDF

Download and setup the ESP-IDF.

Step 2 - Get the lwIP library with NAT

Download the repository of the NAT lwIP library using the follwing command:

git clone https://github.com/martin-ger/esp-lwip.git

Note: It is important to clone the repository. If it is only downloaded it will be replaced by the orginal lwIP library during the build.

Step 3 - Replace original ESP-IDF lwIP library with NAT lwIP library

  1. Go to the folder where the ESP-IDF is installed.
  2. Rename or delete the esp-idf/component/lwip/lwip directory.
  3. Move the lwIP library with NAT repository folder from Step 2 to esp-idf/component/lwip/
  4. Rename the lwIP library with NAT repository folder from esp-lwip to lwip.

Step 4 - Build and flash the esp-idf-nat-example project

  1. Configure and set the option "Enable copy between Layer2 and Layer3 packets" in the ESP-IDF project configuration.
    1. In the project directory run make menuconfig (or idf.py menuconfig for cmake).
    2. Go to Component config -> LWIP and set "Enable copy between Layer2 and Layer3 packets" option.
  2. Build the project and flash it to the ESP32.

A detailed instruction on how to build, configure and flash a ESP-IDF project can also be found the official ESP-IDF guide.

DNS

By Default the DNS-Server which is offerd to clients connecting to the ESP32 AP is set to 8.8.8.8. Replace the value of the MY_DNS_IP_ADDR with your desired DNS-Server IP address (in hex) if you want to use a different one.

Troubleshooting

Line Endings

The line endings in the Console Example are configured to match particular serial monitors. Therefore, if the following log output appears, consider using a different serial monitor (e.g. Putty for Windows or GtkTerm on Linux) or modify the example's UART configuration.

This is an example of ESP-IDF console component.
Type 'help' to get the list of commands.
Use UP/DOWN arrows to navigate through command history.
Press TAB when typing command name to auto-complete.
Your terminal application does not support escape sequences.
Line editing and history features are disabled.
On Windows, try using Putty instead.
esp32>