Skills
skills/aradotso/trending-skills/mhr-cfw-domain-fronting-relay

mhr-cfw-domain-fronting-relay

Installation
SKILL.md

MHR-CFW Domain-Fronting Relay

Skill by ara.so — Daily 2026 Skills collection.

MHR-CFW (MasterHttpRelay + Cloudflare Worker) is a Python-based domain-fronting relay that routes HTTP/SOCKS5 proxy traffic through Google Apps Script (GAS) and Cloudflare Workers. Network DPI filters see only traffic to www.google.com, while the actual destination is hidden inside the relay chain.

Traffic Flow

Client → Local Proxy (127.0.0.1:8085)
           ↓
       Google IP (216.239.38.120) — DPI sees www.google.com
           ↓
       Google Apps Script Web App (Relay)
           ↓
       Cloudflare Worker
           ↓
       Target Website

Installation

git clone https://github.com/denuitt1/mhr-cfw.git
cd mhr-cfw
pip install -r requirements.txt

If PyPI is blocked:

pip install -r requirements.txt \
  -i https://mirror-pypi.runflare.com/simple/ \
  --trusted-host mirror-pypi.runflare.com

Full Setup Guide

Step 1: Deploy the Cloudflare Worker

  1. Log in to Cloudflare Dashboard
  2. Navigate to Compute > Workers & Pages
  3. Click Create Application → Start with Hello World → Deploy
  4. Click Edit code, delete all default code
  5. Paste the contents of script/worker.js from the repo
  6. Edit the worker URL constant: 
    const WORKER_URL = "your-worker-name.workers.dev";
  7. Click Deploy — note your worker URL (e.g., your-worker-name.workers.dev)

Step 2: Deploy the Google Apps Script Relay

  1. Go to script.google.com and create a New project
  2. Delete all default code
  3. Paste the contents of script/Code.gs from the repo
  4. Edit these two constants at the top: 
    const AUTH_KEY = "your-secret-password-here";   // choose a strong password
const WORKER_URL = "https://your-worker-name.workers.dev";
  5. Click Deploy → New deployment
    • Type: Web app
    • Execute as: Me
    • Who has access: Anyone
  6. Click Deploy and copy the Deployment ID (long random string like AKfycb...)

Step 3: Configure config.json

cp config.example.json config.json

Edit config.json:

{
  "mode": "apps_script",
  "google_ip": "216.239.38.120",
  "front_domain": "www.google.com",
  "script_id": "AKfycbXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX",
  "auth_key": "your-secret-password-here",
  "listen_host": "127.0.0.1",
  "listen_port": 8085,
  "socks5_enabled": true,
  "socks5_port": 1080,
  "log_level": "INFO",
  "verify_ssl": true
}
Field Description
mode Always "apps_script" for GAS relay
google_ip IP of Google's infrastructure for fronting
front_domain Domain shown to DPI (www.google.com)
script_id Your GAS Deployment ID from Step 2
auth_key Must match AUTH_KEY in Code.gs
listen_host Local bind address (keep 127.0.0.1)
listen_port HTTP proxy port (default 8085)
socks5_enabled Enable SOCKS5 proxy on socks5_port
socks5_port SOCKS5 proxy port (default 1080)
log_level DEBUG, INFO, WARNING, ERROR
verify_ssl Verify SSL certs; set false to skip

Step 4: Run the Proxy

Linux/macOS:

bash start.sh
# or
python3 main.py

Windows:

start.bat

Expected output:

[INFO] HTTP proxy running on 127.0.0.1:8085
[INFO] SOCKS5 proxy running on 127.0.0.1:1080

Using the Proxy

Browser via FoxyProxy

Install FoxyProxy:

Configure FoxyProxy:

  • Proxy Type: HTTP or SOCKS5
  • Host: 127.0.0.1
  • Port: 8085 (HTTP) or 1080 (SOCKS5)

curl (HTTP proxy)

curl -x http://127.0.0.1:8085 https://ipleak.net/json/

curl (SOCKS5 proxy)

curl --socks5 127.0.0.1:1080 https://ipleak.net/json/

Python requests

import requests

proxies = {
    "http": "http://127.0.0.1:8085",
    "https": "http://127.0.0.1:8085",
}

response = requests.get("https://ipleak.net/json/", proxies=proxies)
print(response.json())

Python with SOCKS5

import requests

proxies = {
    "http": "socks5://127.0.0.1:1080",
    "https": "socks5://127.0.0.1:1080",
}

response = requests.get("https://ipleak.net/json/", proxies=proxies)
print(response.json())

Configuration Patterns

Minimal config (HTTP only, no SOCKS5)

{
  "mode": "apps_script",
  "google_ip": "216.239.38.120",
  "front_domain": "www.google.com",
  "script_id": "YOUR_DEPLOYMENT_ID",
  "auth_key": "YOUR_AUTH_KEY",
  "listen_host": "127.0.0.1",
  "listen_port": 8085,
  "socks5_enabled": false,
  "log_level": "INFO",
  "verify_ssl": true
}

Debug config (verbose logging, skip SSL verification)

{
  "mode": "apps_script",
  "google_ip": "216.239.38.120",
  "front_domain": "www.google.com",
  "script_id": "YOUR_DEPLOYMENT_ID",
  "auth_key": "YOUR_AUTH_KEY",
  "listen_host": "127.0.0.1",
  "listen_port": 8085,
  "socks5_enabled": true,
  "socks5_port": 1080,
  "log_level": "DEBUG",
  "verify_ssl": false
}

Listen on all interfaces (for LAN sharing)

{
  "listen_host": "0.0.0.0",
  "listen_port": 8085
}

⚠️ Only use 0.0.0.0 on trusted networks. Anyone on the LAN can use your proxy.

Cloudflare Worker (script/worker.js) — Key Structure

// The worker receives proxied requests and forwards them to the target
const WORKER_URL = "your-worker-name.workers.dev"; // set this to your own worker

addEventListener("fetch", event => {
  event.respondWith(handleRequest(event.request));
});

The worker:

  • Receives requests from GAS relay
  • Extracts the target URL from the request
  • Fetches the target on behalf of the client
  • Returns the response back through the chain

Google Apps Script (script/Code.gs) — Key Structure

const AUTH_KEY = "your-secret-password-here";      // must match config.json auth_key
const WORKER_URL = "https://your-worker.workers.dev";

function doPost(e) {
  // Validates AUTH_KEY, extracts target URL, forwards via WORKER_URL
}

The GAS relay:

  • Exposes a public HTTPS endpoint (/exec) that acts as the domain-fronted relay
  • Validates AUTH_KEY on every request
  • Forwards validated requests to your Cloudflare Worker

Verifying It Works

After starting the proxy and configuring your browser:

  1. Visit ipleak.net — your IP should show as a Cloudflare IP
  2. Visit whoer.net — should reflect Cloudflare's location
  3. Via curl: 
    curl -x http://127.0.0.1:8085 https://ipleak.net/json/ | python3 -m json.tool
    Look for "ip" showing a Cloudflare address range.

Troubleshooting

Proxy starts but no traffic gets through

  • Verify script_id in config.json is the Deployment ID, not the Script ID
  • Re-check that auth_key in config.json exactly matches AUTH_KEY in Code.gs
  • In GAS, confirm deployment is set to Execute as: Me and Who has access: Anyone
  • Try redeploying the GAS app — old deployments sometimes break

SSL errors

"verify_ssl": false

Set to false temporarily to diagnose. Re-enable for production use.

pip install fails (PyPI blocked)

pip install -r requirements.txt \
  -i https://mirror-pypi.runflare.com/simple/ \
  --trusted-host mirror-pypi.runflare.com

GAS quota exceeded

Google Apps Script has daily quotas (~20,000 URL fetch calls/day for free accounts). If the relay stops working mid-day:

  • Use a different Google account for a fresh GAS deployment
  • Deploy multiple GAS relays and alternate script_id values

Port already in use

{
  "listen_port": 8086,
  "socks5_port": 1081
}

Change ports in config.json and update your browser/FoxyProxy settings.

Cloudflare Worker errors (5xx)

  • Check the worker is deployed and the WORKER_URL in Code.gs matches exactly
  • Visit https://your-worker.workers.dev directly in browser — should respond (even with an error page) rather than timeout
  • Check Cloudflare Worker logs in the dashboard under Workers & Pages > your worker > Logs

Debug logging

"log_level": "DEBUG"

Restart main.py — you'll see each relay hop logged to stdout.

Environment Variable Pattern for Automation

When scripting deployment or CI, avoid hardcoding secrets. Use environment variables and generate config dynamically:

import json
import os

config = {
    "mode": "apps_script",
    "google_ip": "216.239.38.120",
    "front_domain": "www.google.com",
    "script_id": os.environ["GAS_DEPLOYMENT_ID"],
    "auth_key": os.environ["MHR_AUTH_KEY"],
    "listen_host": "127.0.0.1",
    "listen_port": int(os.environ.get("MHR_PORT", "8085")),
    "socks5_enabled": True,
    "socks5_port": 1080,
    "log_level": os.environ.get("MHR_LOG_LEVEL", "INFO"),
    "verify_ssl": True
}

with open("config.json", "w") as f:
    json.dump(config, f, indent=2)

print("config.json written")

Then run:

export GAS_DEPLOYMENT_ID="AKfycbXXXXXXXXXXXXXX"
export MHR_AUTH_KEY="$(openssl rand -hex 32)"
python3 write_config.py
python3 main.py

Project File Reference

File Purpose
main.py Entry point — starts HTTP and SOCKS5 proxy listeners
config.json Runtime configuration (copy from config.example.json)
config.example.json Template configuration with placeholder values
script/worker.js Cloudflare Worker source — deploy to Cloudflare
script/Code.gs Google Apps Script relay source — deploy to GAS
start.bat Windows launcher
start.sh Linux/macOS launcher
requirements.txt Python dependencies
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