Ethernut is the name of an Open Source Hardware and Software Project for building Embedded Ethernet Devices.The hardware part is a small board, also named Ethernut.
You can run the Contiki Operating System on an Ethernut.
Ethernut 1.3 Hardware
PCB Version 1.3 Revision G
4-layer board with ATmega128 running at 14.7456 MHz, 10 MBit Realtek Ethernet Controller and 32 kByte external SRAM.