This Ethernet Shield which is based on the Wiznet W5100 Ethernet Chip
It adds a micro-SD card slot, which can be used to store files for serving over the network.
It is compatible with the Arduino Duemilanove (168 or 328), Uno as well as Mega (1280/2560) and can be accessed using the SD library.
The Wiznet W5100 provides a network (IP) stack capable of both TCP and UDP.
It supports up to four simultaneous socket connections.
Use the Ethernet library to write sketches which connect to the internet using the shield.
Direct plug puzzle board, NO soldering needed.
The Ethernet shield allows you to connect a WizNet Ethernet controller to the Arduino via the SPI bus. It uses pins 10, 11, 12, and 13 for the SPI connection to the WizNet. Later models of the Ethernet shield also have an SD Card on board. Digital pin 4 is used to control the slave select pin on the SD card.
Бывает что ethernet модуль зависает, останавливая всю плату. Решение проблемы hard reset.