Cloudflare Dynamic DNS

A Python script that keeps your Cloudflare DNS records updated with your current public IP. Useful for home servers, self-hosted services, or anywhere you need DNS to track a changing IP address.

Features

• Automatic discovery - Finds zones and records on its own; no need to look up IDs manually
• IPv4 and IPv6 - Updates both A and AAAA records
• Change detection - Only pushes updates when your IP actually changes
• History tracking - SQLite database logs all updates with timestamps
• Systemd integration - Logs to the journal and syslog for easy monitoring
• Multiple subdomains - Update as many records as you need in a single run

Setup

1. Install Dependencies

pip install -r requirements.txt

2. Configure API Credentials

Create ./data/.env with your Cloudflare credentials:

CF_API_EMAIL=your-email@example.com
CF_API_KEY=your-api-token-here

Getting an API token:

1. Go to Cloudflare Dashboard → My Profile → API Tokens
2. Click Create Token and use the "Edit zone DNS" template
3. Set permissions to Zone → DNS → Edit
4. Copy the token into your .env file

You can also use a Global API Key instead of a token, but tokens are more secure since they can be scoped to specific permissions.

3. Configure Subdomains

Add the subdomains you want to update to ./data/dnsrecords.txt, one per line:

home.example.com
vpn.example.com:A
server.example.com:AAAA

By default, both A (IPv4) and AAAA (IPv6) records are updated. Append :A or :AAAA to limit it to one type.

Alternatively, you can edit the subdomains_config list in core.py directly.

Usage

Manual Execution

python3 core.py

Systemd Service

Create a systemd service file (e.g., /etc/systemd/system/cloudflare-dns.service):

[Unit]
Description=Cloudflare Dynamic DNS Updater
After=network.target

[Service]
Type=oneshot
User=your-username
WorkingDirectory=/path/to/cloudflare-dynamic-dns
ExecStart=/usr/bin/python3 /path/to/cloudflare-dynamic-dns/core.py
Environment="PATH=/usr/bin:/usr/local/bin"

[Install]
WantedBy=multi-user.target

Create a timer to run it periodically (e.g., /etc/systemd/system/cloudflare-dns.timer):

[Unit]
Description=Run Cloudflare DNS updater every 5 minutes
Requires=cloudflare-dns.service

[Timer]
OnBootSec=1min
OnUnitActiveSec=5min

[Install]
WantedBy=timers.target

Enable and start the timer:

sudo systemctl enable cloudflare-dns.timer
sudo systemctl start cloudflare-dns.timer

How It Works

1. Detects your current public IPv4 and IPv6 addresses
2. For each subdomain, finds the matching Cloudflare zone and DNS record
3. Compares the current IP with what's in DNS
4. Updates the record if they differ, adding a timestamp to the record comment
5. Logs everything to a local SQLite database and the system journal

Database

All state is stored in ./data/cloudflare_dns.db. The database tracks:

• last_ips - Current IP for each subdomain/record type
• update_history - Full log of every update attempt

Some useful queries:

# Recent updates
sqlite3 ./data/cloudflare_dns.db "SELECT * FROM update_history ORDER BY updated_at DESC LIMIT 10;"

# Failed updates only
sqlite3 ./data/cloudflare_dns.db "SELECT * FROM update_history WHERE success = 0;"

The database is created automatically on first run.

Logging

Output goes to stdout, syslog, and the systemd journal (if available). You can also enable file logging with rotation by adding these to your .env:

LOG_FILE="./data/cloudflare-dns.log"
LOG_MAX_MB=10        # Max size before rotation (default: 10)
LOG_BACKUP_COUNT=5   # Number of old logs to keep (default: 5)

View systemd logs with:

journalctl -u cloudflare-dns.service -f

IPv6 Support

If you have a public IPv6 address, it will be detected and used for AAAA records. If not, AAAA updates are skipped silently and A records are still processed.

Requirements

• Python 3.6+
• requests
• python-dotenv
• systemd (optional, for journal logging)

Troubleshooting

"DNS record not found" - The subdomain must already exist in Cloudflare. This script updates records, it doesn't create them.

"Failed to get public IP" - Check your internet connection. The IP lookup services may also be temporarily down.

"Cloudflare API error" - Double-check your credentials and make sure your token has DNS:Edit permissions for the zone.

License

See LICENSE file for details.