QuecPython NAT Configuration

QuecPython
1

Hi everyone,

I’m working on a project where I need to host a web server behind a Quectel EC200A modem and access it directly through the modem’s public IP address.

Working Configuration

When using the default EC200A firmware (without QuecPython), I can disable NAT using:

AT+QCFG="nat",0

After rebooting the module, both ECM and RNDIS modes work correctly:

  • The EC200A receives a public IP address from the cellular network.

  • Devices connected through ECM/RNDIS can be reached from the Internet.

  • I can access my local web server using the public IP assigned to the EC200A.

Problem with QuecPython Firmware

After flashing the QuecPython firmware on the same EC200A module, the behavior changes.

I can still execute:

AT+QCFG="nat",0

and the command appears to be accepted, but incoming connections from the Internet no longer reach the web server.

Current Observations

  • Same hardware.

  • Same SIM card and cellular operator.

  • Same ECM/RNDIS configuration.

  • Public IP is still assigned to the modem.

  • Web server works locally.

  • Outgoing Internet access works normally.

  • Incoming connections to the public IP fail when QuecPython firmware is installed.

Questions

  1. Does QuecPython firmware handle networking differently from the standard firmware?

  2. Is there an additional firewall, routing, or NAT layer enabled by QuecPython?

  3. Does AT+QCFG="nat",0 have the same functionality in QuecPython firmware?

  4. Are there additional settings required to expose services on the public IP when using QuecPython?

Any guidance or experience with EC200A + QuecPython networking behavior would be appreciated.

Thank you.

2

Dear Customer

yes,QuecPython differs from the standard solution. In QuecPython, development mainly uses APIs, while the standard solution uses AT commands for development.

In QuecPython, you can refer to the following link for network card dial-up (RNDIS/ECM)

USBNET - USB Network Card - QuecPython

USB Network Adapter - QuecPython

For QuecPython, we have uploaded all the documentation and resources online. Please refer to the link below.

Download (including materials and tools)

wiki（QuecPython API Reference Manual）

Document