Netgear LM1200 SMS Gateway

Automated SMS reception and forwarding for Netgear LM1200 4G LTE Modem — 2FA/OTP codes directly to Telegram.

⚡ Features

• 📱 Automatic SMS polling (every 5 minutes via systemd timer)
• 📨 Optional Telegram forwarding for 2FA/OTP codes
• 💾 Local JSON storage (monthly rotated files)
• 🔄 State management (no duplicates, no lost messages)
• 🔒 Hash-based deduplication (robust against ID resets)
• 🐍 Python 3.10+ with async/await
• 🔒 systemd security hardening
• 🔐 Optional SMS Encryption (AES-256 via Fernet)
• 🔄 Retry Logic (exponential backoff for transient errors)
• 🏥 Health-Check Endpoint (monitoring integration)

🚨 Critical: Germany-Specific Setup

IMPORTANT: SMS reception requires specific modem configuration:

1. ✅ Network Mode: "Auto" (NOT "LTE Only"!)
2. ✅ SMS Alerts: Enabled in modem settings

Without these settings, SMS will NOT be received. See docs/TROUBLESHOOTING.md for details.

🚀 Quick Start

Prerequisites

• Netgear LM1200 4G LTE Modem with active SIM card
• Linux system with Python 3.10+ and systemd
• jq command-line JSON processor (for SMS parsing)
• (Optional) Telegram Bot Token for SMS forwarding

Install jq:

# Debian/Ubuntu
sudo apt install jq

# RHEL/Fedora
sudo dnf install jq

Installation

1. Clone repository:

   git clone https://github.com/fidpa/netgear-lm1200-sms-gateway
   cd netgear-lm1200-sms-gateway

2. Install dependencies:

   python3 -m venv venv
   source venv/bin/activate
   pip install -r requirements.txt

3. Configure modem (CRITICAL!):

   • Open modem web UI: http://192.168.0.201
   • Set Network Mode to "Auto" (Network → LTE Settings → Band Selection)
   • Enable SMS Alerts (Settings → General → Alerts → "On")

4. Create configuration:

   sudo mkdir -p /etc/netgear-sms-gateway
   sudo cp config/config.example.env /etc/netgear-sms-gateway/config.env
   sudo nano /etc/netgear-sms-gateway/config.env

5. Install systemd units:

   sudo cp systemd/*.{service,timer} /etc/systemd/system/
   
   # IMPORTANT: Edit service file and replace YOUR_USERNAME with your actual username
   sudo nano /etc/systemd/system/netgear-sms-poller.service
   # Change: User=YOUR_USERNAME → User=yourname
   # Change: Group=YOUR_USERNAME → Group=yourname
   
   sudo systemctl daemon-reload
   sudo systemctl enable --now netgear-sms-poller.timer

6. Create symlink (REQUIRED):

   sudo ln -sf "$(pwd)/src/netgear_sms_wrapper.sh" /usr/local/bin/netgear-sms-poller

7. Test:

   # Send test SMS to modem SIM card
   # Wait 5 minutes or trigger manually:
   sudo systemctl start netgear-sms-poller.service
   
   # Check logs:
   journalctl -u netgear-sms-poller.service -n 50

📖 Documentation

• Documentation Index - Overview & quick links
• Setup Guide - Detailed installation & configuration
• API Reference - Complete API documentation
• Troubleshooting - Common issues & solutions

🔧 Configuration

Minimal (SMS Storage Only)

# /etc/netgear-sms-gateway/config.env
NETGEAR_IP=192.168.0.201
NETGEAR_ADMIN_PASSWORD=your_admin_password
SMS_STATE_DIR=/var/lib/netgear-sms-gateway

Optional (With Telegram Forwarding)

TELEGRAM_BOT_TOKEN=123456789:ABC...
TELEGRAM_CHAT_ID=12345678
TELEGRAM_PREFIX="[SMS Gateway]"
RATE_LIMIT_SECONDS=300

Advanced Configuration

Debug Logging

LOG_LEVEL=DEBUG  # Shows detailed hash checks, ID comparisons

SMS Encryption (Optional)

Requires: pip install cryptography>=42.0.0

SMS_ENCRYPTION_ENABLED=true
SMS_ENCRYPTION_KEY_FILE=/etc/netgear-sms-gateway/.encryption.key

Generate key: ./src/netgear_sms_poller.py generate-key

See docs/ENCRYPTION.md for full guide.

Note: Gateway works without encryption - install only if you need this feature.

Health Check

./src/netgear_sms_poller.py health
# Returns: 0 (healthy), 1 (degraded), 2 (down)

See docs/MONITORING.md for integration examples.

🛡️ Security

• Credentials stored in /etc/netgear-sms-gateway/config.env (chmod 600)
• systemd sandboxing: ProtectSystem=strict, PrivateTmp=yes
• SMS content stored in /var/lib/netgear-sms-gateway/ (restricted access)

For vulnerability reporting and security best practices, see SECURITY.md.

📊 Use Cases

• ✅ 2FA/OTP code reception (banking, services)
• ✅ Automated SMS backup/archival
• ✅ SMS-to-Telegram bridge for mobile access
• ✅ Home automation SMS triggers

🤝 Contributing

Contributions welcome! Please see CONTRIBUTING.md for guidelines.

📜 License

MIT License - see LICENSE file for details.

🔗 Related Projects

• svbnet/netgear-sms - SMS API for Netgear LTE modems
• Home Assistant NETGEAR LTE Integration