The ethernet shield connects to an Arduino board using long wire-wrap headers which extend through the shield. This keeps the pin layout intact and allows another shield to be stacked on top.
Arduino uses digital pins 10, 11, 12, and 13 (SPI) to communicate with the W5100 on the ethernet shield. These pins cannot be used for general i/o.
The shield provides a standard RJ45 ethernet jack. An Arduino is necessary to use this shield but is not included.
For more information, check out the Getting started guide
Before you do this tutorial you’ll want to get familiar with what you’re working on. This isn’t a beginner tutorial, its best used by those who already have quite a bit Arduino or microcontroller experience and are ‘fluent’ in C/C++/Java!
1 x Ethernet Shield W5100