Arduino DDNS (Dynamic DNS)

By on April 8, 2011
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This device captures the IP address of your network and it publish on site All without PC. It allow a remote access to your LAN even if the IP address of the connections changes.
For logistics reasons the provider can not assign a IP fixed for all users, so many users, especially private, work with a dynamic IP or public IP: in practice when they connect modem or router, to their connection is assigned an IP address that, when the connection will’be closed, can be used by other users. This makes impossible to contact a remote computer or device connected to a LAN Internet.

If you want to access to a device connected to your home LAN (so not with static IP) you must use a service like DynDNS, because every time you connect your ISP dynamically assigns a new IP address.

If you don’t want to use the software provided by DynDNS, and then leave the PC switched on continuously, the solution is this project.
Our device queries the site to know the IP currently used for the connection, and then publish your free account to instead of the computer acquired the new IP. Such a device therefore allows to locate a LAN connected to the Internet via a router or modem network.

Our device is essentially a publisher of IP address. Everything is made ​​from a circuit that incorporates an Ethernet interface WIZnet WIZ811MJ, managed by an Atmega328 microcontroller programmed with the Arduino bootloader, so it all works like an Arduino and you can use the Arduino IDE. The Atmega I/O PB2, PB3, PB4 and PB5 are dedicated to dialogue with the Ethernet module and provide a full four-wire SPI bus. The microcontroller is programmed using the special interface TTL / USB from SparkFun.
The main program sends the request to the IP address site. Now prepare the process of submitting to the site, which provides for the opening of a session onthe web page on, where will send data strings containing user name and password, thena string containing the Current IP connection. Cyclically
the microcontroller check the IP to see if the address is changed, then, if it’s true, sends the new IP to

We use a dedicated circuit but the project can be replicated using an Arduino UNO and a Ethernet Shield.

Sketch Code for Arduino DDNS (Dynamic DNS)


Download ZIP File

Download the DDNS sketch for Arduino


About Boris Landoni

Boris Landoni is the technical manager of Skilled in the GSM field, embraces the Open Source philosophy and its projects are available to the community.


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