nextdns-blocker 5.0.0

Automated domain blocking controller for NextDNS with per-domain scheduling

NextDNS Blocker

Automated system to control domain access with per-domain schedule configuration using the NextDNS API.

Features

• Per-domain scheduling: Configure unique availability hours for each domain
• Flexible time ranges: Multiple time windows per day, different schedules per weekday
• Protected domains: Mark domains as protected to prevent accidental unblocking
• Pause/Resume: Temporarily disable blocking without changing configuration
• Automatic synchronization: Runs every 2 minutes via cron with watchdog protection
• Timezone-aware: Respects configured timezone for schedule evaluation
• Secure: File permissions, input validation, and audit logging
• NextDNS API integration: Works via NextDNS denylist
• Dry-run mode: Preview changes without applying them
• Smart caching: Reduces API calls with intelligent denylist caching
• Rate limiting: Built-in protection against API rate limits
• Exponential backoff: Automatic retries with increasing delays on failures

Requirements

• Python 3.9+
• NextDNS account with API key
• Linux/macOS/Windows

Installation

Option 1: Install from PyPI (Recommended)

pip install nextdns-blocker

Then run the setup wizard:

nextdns-blocker init

Option 2: Install from Source

git clone https://github.com/aristeoibarra/nextdns-blocker.git
cd nextdns-blocker
pip install -e .
nextdns-blocker init

Quick Setup

1. Get NextDNS Credentials

• API Key: https://my.nextdns.io/account
• Profile ID: From URL (e.g., https://my.nextdns.io/abc123 -> abc123)

2. Run Setup Wizard

nextdns-blocker init

The wizard will prompt for:

• API Key
• Profile ID
• Timezone
• Option to create sample domains.json

3. Configure Domains and Schedules

Edit domains.json in your config directory to configure your domains and their availability schedules.

See SCHEDULE_GUIDE.md for detailed schedule configuration examples.

4. Install Watchdog (Optional)

For automatic syncing every 2 minutes with cron:

nextdns-blocker watchdog install

Done! The system will now automatically sync based on your configured schedules.

Docker Setup

Alternatively, run NextDNS Blocker using Docker:

1. Configure Environment

cp .env.example .env
nano .env  # Add your API key, profile ID, and timezone

2. Configure Domains

cp domains.json.example domains.json
nano domains.json  # Configure your domains and schedules

3. Run with Docker Compose

docker compose up -d

Docker Commands

# View logs
docker compose logs -f

# Stop the container
docker compose down

# Rebuild after changes
docker compose up -d --build

# Check status
docker compose ps

# Run a one-time sync
docker compose exec nextdns-blocker python nextdns_blocker.py sync -v

# Check blocking status
docker compose exec nextdns-blocker python nextdns_blocker.py status

Environment Variables for Docker

Variable	Required	Default	Description
NEXTDNS_API_KEY	Yes	-	Your NextDNS API key
NEXTDNS_PROFILE_ID	Yes	-	Your NextDNS profile ID
DOMAINS_URL	No	-	URL to fetch domains.json remotely
TZ	No	America/Mexico_City	Container timezone

Commands

Main Blocker Commands

# Sync based on schedules (runs automatically every 2 min)
nextdns-blocker sync

# Preview what sync would do without making changes
nextdns-blocker sync --dry-run

# Sync with verbose output showing all actions
nextdns-blocker sync --verbose
nextdns-blocker sync -v

# Check current blocking status
nextdns-blocker status

# Manually unblock a domain (won't work on protected domains)
nextdns-blocker unblock example.com

# Pause all blocking for 30 minutes (default)
nextdns-blocker pause

# Pause for custom duration (e.g., 60 minutes)
nextdns-blocker pause 60

# Resume blocking immediately
nextdns-blocker resume

Watchdog Commands

# Check cron status
nextdns-blocker watchdog status

# Disable watchdog for 30 minutes
nextdns-blocker watchdog disable 30

# Disable watchdog permanently
nextdns-blocker watchdog disable

# Re-enable watchdog
nextdns-blocker watchdog enable

# Manually install cron jobs
nextdns-blocker watchdog install

# Remove cron jobs
nextdns-blocker watchdog uninstall

Logs

# View application logs
tail -f ~/.local/share/nextdns-blocker/logs/app.log

# View audit log (all blocking/unblocking actions)
cat ~/.local/share/nextdns-blocker/logs/audit.log

# View cron execution logs
tail -f ~/.local/share/nextdns-blocker/logs/cron.log

# View watchdog logs
tail -f ~/.local/share/nextdns-blocker/logs/wd.log

# View cron jobs
crontab -l

Configuration

Environment Variables (.env)

Variable	Required	Default	Description
NEXTDNS_API_KEY	Yes	-	Your NextDNS API key
NEXTDNS_PROFILE_ID	Yes	-	Your NextDNS profile ID
TIMEZONE	No	UTC	Timezone for schedule evaluation
API_TIMEOUT	No	10	API request timeout in seconds
API_RETRIES	No	3	Number of retry attempts
DOMAINS_URL	No	-	URL to fetch domains.json from

Domain Schedules

Edit domains.json to configure which domains to manage and their availability schedules:

{
  "domains": [
    {
      "domain": "reddit.com",
      "description": "Social media",
      "protected": false,
      "schedule": {
        "available_hours": [
          {
            "days": ["monday", "tuesday", "wednesday", "thursday", "friday"],
            "time_ranges": [
              {"start": "12:00", "end": "13:00"},
              {"start": "18:00", "end": "22:00"}
            ]
          },
          {
            "days": ["saturday", "sunday"],
            "time_ranges": [
              {"start": "10:00", "end": "22:00"}
            ]
          }
        ]
      }
    },
    {
      "domain": "gambling-site.com",
      "description": "Always blocked",
      "protected": true,
      "schedule": null
    }
  ]
}

Domain Configuration Options

Field	Required	Description
domain	Yes	Domain name to manage
description	No	Human-readable description
protected	No	If true, domain cannot be manually unblocked
schedule	No	Availability schedule (null = always blocked)

Changes take effect on next sync (every 2 minutes).

See SCHEDULE_GUIDE.md for complete documentation and examples.

Allowlist (Exceptions)

Use the allowlist to keep specific subdomains accessible even when their parent domain is blocked:

{
  "domains": [
    {
      "domain": "amazon.com",
      "description": "E-commerce - blocked with schedule",
      "schedule": { ... }
    }
  ],
  "allowlist": [
    {
      "domain": "aws.amazon.com",
      "description": "AWS Console - always accessible"
    },
    {
      "domain": "developer.amazon.com",
      "description": "Amazon Developer - always accessible"
    }
  ]
}

Allowlist Behavior

• Allowlist entries are always active 24/7 (no schedule support)
• A domain cannot be in both domains (denylist) and allowlist
• Use for subdomain exceptions: block amazon.com but allow aws.amazon.com
• Changes sync automatically every 2 minutes

Allowlist Commands

# Add domain to allowlist (always accessible)
nextdns-blocker allow aws.amazon.com

# Remove domain from allowlist
nextdns-blocker disallow aws.amazon.com

# View current status including allowlist
nextdns-blocker status

Timezone

Edit .env to change timezone:

TIMEZONE=America/New_York

See list of timezones.

Troubleshooting

Sync not working?

• Check cron: crontab -l (should see sync job running every 2 minutes)
• Check logs: tail -f ~/.local/share/nextdns-blocker/logs/app.log
• Test manually: nextdns-blocker sync
• Validate JSON: python3 -m json.tool domains.json

Domains.json errors?

• Ensure valid JSON syntax (use jsonlint.com)
• Check time format is HH:MM (24-hour)
• Check day names are lowercase (monday, tuesday, etc.)
• Domain names must be valid (no spaces, special characters)
• See domains.json.example for reference

Wrong timezone?

• Update TIMEZONE in .env
• Re-run ./install.sh
• Check logs to verify timezone is being used

API timeouts?

• Increase API_TIMEOUT in .env (default: 10 seconds)
• Increase API_RETRIES in .env (default: 3 attempts)

Cron not running?

# Check cron service status
sudo service cron status || sudo service crond status

# Check watchdog status
nextdns-blocker watchdog status

Uninstall

# Remove cron jobs
nextdns-blocker watchdog uninstall

# Remove files
rm -rf ~/nextdns-blocker

# Remove logs (optional)
rm -rf ~/.local/share/nextdns-blocker

Log Rotation

To prevent log files from growing indefinitely, set up log rotation:

chmod +x setup-logrotate.sh
./setup-logrotate.sh

This configures automatic rotation with:

• app.log: daily, 7 days retention
• audit.log: weekly, 12 weeks retention
• cron.log: daily, 7 days retention
• wd.log: daily, 7 days retention

Development

Running Tests

pip install -e ".[dev]"
pytest tests/ -v

Test Coverage

pytest tests/ --cov=nextdns_blocker --cov-report=html

Current coverage: 85% with 379 tests.

Code Quality

The codebase follows these practices:

• Type hints on all functions
• Docstrings with Args/Returns documentation
• Custom exceptions for error handling
• Secure file permissions (0o600)
• Input validation before API calls

Documentation

• SCHEDULE_GUIDE.md - Complete schedule configuration guide with examples
• domains.json.example - Example configuration file
• CONTRIBUTING.md - Contribution guidelines

Security

• Never share your .env file (contains API key)
• .gitignore is configured to ignore sensitive files
• All API requests use HTTPS
• Sensitive files created with 0o600 permissions
• Domain names validated before API calls
• Audit log tracks all blocking/unblocking actions

License

MIT