查看“Microduino ENC Network (6)”的源代码

{{Language | Microduino ENC网络（六）}}
{| style="width: 800px;"
|-
|
==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:

[[File:noipPhoto.jpg|600px|center|thumb]]

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:

[[File:MicroduinoENCShow.jpg|600px|center|thumb]]


==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:

[[File:getPublicIP.jpg|600px|center|thumb]]

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.

[[File:NoIPAuth.jpg|600px|center|thumb]]

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
[[File:onlineEncode.jpg|600px|center|thumb]]

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==


|}