Useful Networking Libraries
The Ethernet library that comes with the Arduino IDE is fai rl y limited
and not very convenient. For example, it doesn’t support
DNS or DHCP. So for advanced projects, you should have a look
at the Arduino Ethernet library.∗
If you want to turn your Arduino into a web server, you should
take a look at the Webdui no library.† It has some great features,
and it is quite mature.
But be warned: all these libraries consume quite a lot of memory,
so there’s not much left for your application code. Also,
they are rather fragile, because they often rely upon the innards
of the official Ethernet library that change from time to time. So,
it might well be that they do not work with the latest Arduino
IDE.
∗. http://gkaindl.com/software/arduino-ethernet
†. http://code.google.com/p/webduino/