Anyone used the w5100 INT to signal the arduino of data?

Projects Networking, Protocols, and Devices
3

In plain C I did it that way

sei(); //enable external interrupts;
DDRE &= ~(1<<4);  // set the pin 4 onPORT E on input
EIMSK = 0b00010000; //Set the External Interrupt Mask Register
SPI_Write (IMR,0xFF); //enable all interrupts in w5100

Perhaps what you are missing is setting that Interrupt Mask Register (IMR) setup.