Failed to configure Ethernet using DHCP

Projects Networking, Protocols, and Devices
10

You must disable one to start the other. See if this code starts the SD and w5100 ok for you.

#include <SPI.h>
#include <Ethernet.h>
#include <SD.h>

byte mac[] = {  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };

void setup() {
  Serial.begin(9600);

  // disable w5100 SPI while starting SD
  pinMode(10, OUTPUT);
  digitalWrite(10, HIGH);

  Serial.print(F("Starting SD..."));
  if(!SD.begin(4)) Serial.println(F("failed"));
  else Serial.println(F("ok"));

  Serial.print(F("Starting ethernet..."));
  if(!Ethernet.begin(mac)) Serial.println(F("failed"));
  else Serial.println(Ethernet.localIP());
  digitalWrite(10, HIGH);
}

void loop() {
}

I used the F() function to keep the static strings in program memory.