Microduino ENC Network (6)

Language	English

Objective This tutorial will show you how to write a sketch to update a DNS record hosted by one of the most famous Dynamic DNS service providers, no-ip. Equipment Microduino-Core Microduino-FT232R Microduino-ENC28J60 Microduino-RJ45 Other equipment USB cable Dynamic IP addresses If you connect to Internet using a home or mobile connection, you’ll probably have a dynamic public IP address, that is it changes everytime you connect. If you need to talk to a device on Internet, you need to write – in the message you send on the net – its public IP address: if this IP is dynamic, you may not know it. Dynamic DNS In Internet you can find free Dynamic DNS (DDNS) services: they allow you to associate a name you choose with an IP address and they allow you to keep that association updated. The update could be done in different ways: using a client running on your PC; with a feature present in your router: asking Arduino to do it for us. NO-IP One of the most used site offering dynamic DNS service is No-IP. If you register for free to No-IP Free service, you can configure up to 5 hosts for Hosts/Redirects feature: For this tutorial, I registered the following host: enctutorial.no-ip.info. DDNS Client Every DDNS client performs the following steps: gets the actual public IP (asking the router, an external website…); compares that IP with the one resolved from DNS alias; if they are different, it updates the DNS record via service provider’s API. Schematic Microduino-ENC28J60 Microduino-RJ45 Microduino-Core Microduino-FT232R Stack all modules and then connect the ethernet cable, as follows: Program Refer to ENCnetworksix Debug Step 1：Download the EtherCard library and copy to your libraries fold of IDE, then restart IDE. https://github.com/jcw/ethercard Step 2：Explain the program: Public IP: To find the actual public IP, I wrote a simple PHP page on my website: Microduino sketch gets that page and parse the IP address. DNS record and comparison: //Sketch calls dnsLookup() method to resolve actual IP for DNS record; it then converts the result in a String object to use its compareTo() method to compare the two IP addresses: if(!ether.dnsLookup(noIP_host)) { [...] } else { for(int i = 0; i < 4; i++) { dnsIp = dnsIp + String(ether.hisip[i]); if(i < 3) dnsIp = dnsIp + "."; } if(actualIp.compareTo(dnsIp) == 0) { Serial.println("No update needed :)"); [...] } else { Serial.println("Update needed :("); actual_status = STATUS_NOIP_NEEDS_UPDATE; } Authentication: You have to authenticate to No-IP before being allowed to update any records. You have to assign to that constant the base64 encoded value of the string username:password. You can use an online encoder: http://tuxgraphics.org/~guido/javascript/base64-javascript.html Step 3：Compile the code and download it. Step 4：Check if can access the Microduino. Result Arduino correclty found a difference between public IP and DNS record so it updated No-IP record. After a while, it performed another check and this time the two IP addresses were equals so no update was required. Video