What is the best way to send and receive data between multiple Arduino boards using Ethernet Shield?

Question

I'm new to Arduino. I have 4 Arduino boards separated by long distance. I wanted to make connections between all of them so, for example if one sensor connected to Arduino board number 1 (for example) was triggered it will send to all other 3 boards some kind of notification to do action on other boards. I intended to use Ethernet shield but wondered what is the best mode to use when configuring Ethernet Shields with Arduino and how to configure them to do so . I hope you understand. Thank you in advance.

Answer 1

On Arduino with a networking shield you can start an EthernetServer or WiFiServer. See ChatServer example of the Ethernet library.

On other Arduino with a networking shield you create an EthernetClient (or WiFiClient) and connect it to IP address of the server. Then everything you print to client's Client will be send to server's Client returned by server.available().

You can test the server with a Telnet client.