DNS Update Client

README.md

Setup

1. Download this to your device This assumes it will be stored in /home/pi/duckdns.
2. Change the $domains, $token, $ipv4_interface and $ipv6_interface variables in run.php
3. Open root's crontab

   sudo crontab -e
   
   

4. Add this line to the end

   */5 * * * * /home/pi/duckdns/run.sh >/dev/null 2>&1
   
   

   This will make the script run every five minutes - you can change this but you probably won't need to. You may need to change the path to run.sh.

run.php

<?php
	$domains = "pi-1-thewalnutspi";
	$token = "-- duckdns token --";
	$ipv4_interface = "eth0";
	$ipv6_interface = "teredo";
	
	date_default_timezone_set("Europe/London");
	echo date("Y-m-d H:i:s") . " Running update... user: " . get_current_user() . "\n";
	
	// Get the IPv4 address
	// You may want to use a site to get your public IPv4 address, instead of the one assigned to your device
	//$input = system("ip addr show dev teredo | sed -e's/^.*inet6 \([^ ]*\)\/.*$/\1/;t;d'");
	$input = shell_exec("ip addr show dev {$ipv4_interface}");
	
	if(!preg_match_all("/^.*inet ([^ ]*)\/.*$/m", $input, $ip_addresses))
		exit("Failed to read ip addresses: " . str_replace("\n", "\\n", $input) . "\n");
	
	if(!isset($ip_addresses[1]) || !isset($ip_addresses[1][0]))
		exit("Failed to find ip addresses: " . str_replace("\n", "\\n", $input) . "\n");
	$ipv4 = $ip_address = $ip_addresses[1][0];
	
	echo date("Y-m-d H:i:s") . " IP address: " . $ip_address . "\n";
	
	// Get the IPv6 address
	//$input = system("ip addr show dev teredo | sed -e's/^.*inet6 \([^ ]*\)\/.*$/\1/;t;d'");
	$input = shell_exec("ip addr show dev {$ipv6_interface}");
	
	if(!preg_match_all("/^.*inet6 ([^ ]*)\/.*$/m", $input, $ip_addresses))
		exit("Failed to read ip addresses: " . str_replace("\n", "\\n", $input) . "\n");
	
	if(!isset($ip_addresses[1]) || !isset($ip_addresses[1][0]))
		exit("Failed to find ip addresses: " . str_replace("\n", "\\n", $input) . "\n");
	$ipv6 = $ip_address = $ip_addresses[1][0];
	
	echo date("Y-m-d H:i:s") . " IPv6 address: " . $ipv6 . "\n";
	
	// Tell duckdns.org the new IPv4 / IPv6 addresses
	$curl = curl_init();
	curl_setopt($curl, CURLOPT_URL, "https://www.duckdns.org/update?domains={$domains}&token={$token}&ip={$ipv4}&ipv6={$ipv6}&verbose=true");
	curl_setopt($curl, CURLOPT_TIMEOUT, 10);
	curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
	$response = curl_exec($curl);
	echo date("Y-m-d H:i:s") . " Updated {$domains}.duckdns.org: status {$response}\n";
	
	echo "\n";
	

run.sh

php /home/pi/duckdns/run.php > /home/pi/duckdns/output.log