php-cloudflare-dyndns-api

I wrote this script the other day because I needed an easy way to update my Cloudflare DNS records with my periodically changing home IP address.

It's a single PHP file that acts as a wrapper for the Cloudflare API, so you can update records with a single GET request, compatible with most modern routers (TP-Link, Speedport, Fritz!Box, etc.)

Requirements

• Cloudflare account (free)
• Cloudflare API key or API token
• Webserver with PHP 8.1 or higher

Installation

• Make sure a DNS record for the domain you want to update already exists in your Cloudflare account.
• Download cloudflare-dyndns-api.php and upload it to your webserver.
• Open the file and edit preferences to your liking.
  • USE_CACHE · When set to true, the script will write the current IP to a cache file and only update Cloudflare when it has changed.
  • REQUIRE_AUTH · When set to true, username and password are checked before running the script.
  • TURN_ON_LOGGING · When set to true, the script will write to a log file.
  • LOGLEVEL · The log level. Possible values are DEBUG, INFO, WARNING and ERROR.
  • AUTH_USERNAME · Only needed if you use authentication.
  • AUTH_PASSWORD · Only needed if you use authentication. This script has no bruteforce protection, so make sure to choose a strong password if you host this on a publicly reachable webserver.

  const USE_CACHE = TRUE;
  const REQUIRE_AUTH = TRUE;
  const TURN_ON_LOGGING = TRUE;
  const LOGLEVEL = 'INFO';
  const AUTH_USERNAME = 'sunshine';
  const AUTH_PASSWORD = 'abc123';

Usage: Fritz!Box

Open the FRITZ!Box user interface and navigate to Internet -> Permit Access -> DynDNS and fill the fields. Your router will automatically replace the variables <ippaddr> and <ip6addr> with your current IPv4 and IPv6 addresses.

• Domain · The domain you want to update
• User and Password · The credentials you set in the PHP file
• Update-URL · Use the url shown below, but fill in the following values:
  • cfemail · The email address you used to sign up for Cloudflare
  • cfapikey or cfapitoken · Either your Cloudflare API key or your API token. If you set both, the token will be used.

https://example.com/cloudflare-dyndns-api.php?ipv4=<ipaddr>&ipv6=<ip6addr>&user=<username>&pass=<passwd>&domain=<domain>&cfemail=mail@example.com&cfapikey=XXX

Usage: crontab

This cronjob will update the A Record for myhome.example.com every 10 minutes with your current IPv4 address. Make sure to replace the values for the following fields:

• user and pass · The credentials you set in the PHP file
• domain · The domain you want to update
• cfemail · The email address you used to sign up for Cloudflare
• cfapikey or cfapitoken · Either your Cloudflare API key or your API token. If you set both, the token will be used.

*/10 * * * * /usr/bin/curl -sS https://example.com/cloudflare-dyndns-api.php?ipv4=$(curl -sS ifconfig.me)&user=sunshine&pass=abc123&cfemail=mail@example.com&cfapikey=XXX&domain=myhome.example.com