====== Custom DynDNS mit der Fritzbox ======
===== Originalscript =====
von https://dersobi.de/fritzbox-cloudflare-dynamic-dns-update/

  <?php
  // Use script authentication ?
  $sAuth = 1;                 // 0 (False) / 1 (True)
  $username = "wie6Zoh2";    // used if script authentication is enabled 
  $password = "ohgh9Atu";
  
  // Cloudflare DNS Update via API V4
  $email = "cloudflare@admin.email";                  // Cloudflare login e-mail
  $apiKey = "ago5va9uqu9Sae2gasahYoo5ahngaes8ohl3A";  // Cloudflare API Key
  
  // DNS Record options
  $enableProxy = false;  // Toggle Cloudflare proxying for the address  
  $ttl = 1;              // TTL in seconds (1 for auto, or a value greater than 120)
  
  // * Do not edit below this point, unless you know... meh, do what you want * //
  // If auth is enabled check user&pass
  if ($sAuth == 1) {
  if ($_REQUEST['user'] != $username || $_REQUEST['pass'] != $password) {
    exit ("Wrong credentials!");
  }
  }
  
  // Check minimum parameter requirements
  if (!$_REQUEST['domain'] || !$_REQUEST['ipv4']) {
    exit ("Minimum parameter requirements not met!");
  }
  
  $zone = explode('.', $_REQUEST['domain'], 2)[1];  // domain
  $dnsRecord = $_REQUEST['domain'];                 // subdomain 
  $ip4 = $_REQUEST['ipv4'];                         // ipv4 address
  if ($_REQUEST['ipv6']) {
    $ip6 = $_REQUEST['ipv6'];                       // ipv6 address
  }
  
  { // get Zone ID
  $curl = curl_init();
  curl_setopt_array($curl, array(
  CURLOPT_URL => "https://api.cloudflare.com/client/v4/zones",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => array(
    "cache-control: no-cache",
    "X-Auth-Email: ".$email,
    "X-Auth-Key: ".$apiKey
  ),
  ));
  $response = curl_exec($curl);
  $err = curl_error($curl);
  curl_close($curl);
  
  if ($err) {
  exit ("cURL Error #:" . $err);
  } else {
  $obj = json_decode($response,true);
  if( $obj["success"]!=1)
  {
    exit ("GetZoneId Failed");
  }
  $zones =($obj['result']);
  foreach($zones as $zoneResult) {
    if($zoneResult['name']==$zone)
        $zoneId = $zoneResult['id'];
  }
  if ($zoneId =="") {
    exit ("Zone not found!");
  }
  }
  } // end get Zone ID
  
  { // get Record ID
  $curl = curl_init();
  curl_setopt_array($curl, array(
    CURLOPT_URL => "https://api.cloudflare.com/client/v4/zones/".$zoneId."/dns_records",
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_ENCODING => "",
    CURLOPT_MAXREDIRS => 10,
    CURLOPT_TIMEOUT => 30,
    CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
    CURLOPT_CUSTOMREQUEST => "GET",
    CURLOPT_HTTPHEADER => array(
      "Cache-Control: no-cache",
      "X-Auth-Email: ".$email,
      "X-Auth-Key: ".$apiKey
    ),
  ));
  $response = curl_exec($curl);
  $err = curl_error($curl);
  curl_close($curl);
  
  if ($err) {
  exit ("cURL Error #:" . $err);
  } else {
  $obj = json_decode($response,true);
  if( $obj["success"]!=1) {
      exit ("GetRecordID Failed");
  }
  $zones =($obj['result']);
  foreach($zones as $zoneResult) {
      if($zoneResult['name'] == $dnsRecord)
          $recordId[$zoneResult['type']] = $zoneResult['id'];
  }
  }
  } // end get Record ID
  
  { // Update records
  function updateCloudflare($zid, $rid, $eml, $aky, $d, $opr) {
    if ($rid!="") {
      $rid = "/".$rid;
      if ($opr!="DELETE") {
          $opr = "PUT";
      }
    }
    $curl = curl_init();
    curl_setopt_array($curl, array(
      CURLOPT_URL => "https://api.cloudflare.com/client/v4/zones/".$zid."/dns_records".$rid,
      CURLOPT_RETURNTRANSFER => true,
      CURLOPT_ENCODING => "",
      CURLOPT_MAXREDIRS => 10,
      CURLOPT_TIMEOUT => 30,
      CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
      CURLOPT_CUSTOMREQUEST => $opr,
      CURLOPT_HTTPHEADER => array(
        "Cache-Control: no-cache",
        "Content-Type: application/json",
        "X-Auth-Email:".$eml,
        "X-Auth-Key: ".$aky
      )
    ));
    if ($opr!="DELETE") {
      curl_setopt($curl, CURLOPT_POSTFIELDS, json_encode($d));
    }
    $response = curl_exec($curl);
    $err = curl_error($curl);
    curl_close($curl);
    if ($err) {
      exit ("cURL Error #:" . $err);
    } else {
      return json_decode($response);
    }
  } // end function
  // Update/Create ipv4 record
  $data = array (
    'type' => 'A',
    'name' => $dnsRecord,
    'content' => $ip4,
    'proxiable' => true,
    'proxied' => $enableProxy,
    'ttl' => $ttl,
    'locked' => false,
    'zone_id' => $zoneId,
    'zone_name' => $zone
  );
  updateCloudflare($zoneId, $recordId['A'], $email, $apiKey, $data, "POST");
  if ($ip6) {
    $data['type'] = 'AAAA';
    $data['content'] = $ip6;
    updateCloudflare($zoneId, $recordId['AAAA'], $email, $apiKey, $data, "POST");
  } elseif ($recordId['AAAA']) { // we've received no ipv6 address but there is one on Cloudflare
    updateCloudflare($zoneId, $recordId['AAAA'], $email, $apiKey, $data, "DELETE");
  }
  } // end update records
  ?>
You need to open your router DynDNS configuration page, for FRITZ!Box under:
Internet >> Permit Access >> DynDNS
{{:computer:network:pasted:20220321-215217.png}}
Complete the fields as follows:
  "DynDNS Provider": User-defined
  "Update URL": https://yourserver.tld/ddns.php?domain=<domain>&ipv4=<ipaddr>&ipv6=<ip6addr>&user=<username>&pass=<pass>
  "Domain name":     subdomain.yourdomain.tld
  "User name":       wie6Zoh2 (username of your choosing)
  "Password":        ohgh9Atu (choose a password)
In the update URL the “<domain>“, “<username>” and “<pass>” will pass along to the server the corresponding values of the fields below, and “<ipaddr>“, “<ip6addr>” will pass the ipv4 and ipv6 addresses from the FRITZ!Box router.
===== Nutzung =====
Installiert als ''/var/www/html/dyn/dns.php'' auf Pihole mit dem korrekten API-Key von cloudflare.
Aufgerufen von der Fritzbox