I've been working on using an ethernet shield for my Arduino Uno for a couple weeks now. I've been going through the problems one by one and now realise that there seems to be nothing transmitting. Running code similar to DHCPAddressPrinter results in nothing, and any web server I set up does not work at all. Can anyone please help? Running the code below results in an output of "Baud rate set!" and nothing else. One thing to note is that the MAC address I am using is from going into the command prompt and using the MAC address listed from ipconfig /all, as there is no sticker on the ethernet shield itself.

    DHCP-based IP printer

     This sketch uses the DHCP extensions to the Ethernet library
     to get an IP address via DHCP and print the address obtained.
     using an Arduino Wiznet Ethernet shield. 

     * Ethernet shield attached to pins 10, 11, 12, 13

     created 12 April 2011
     modified 9 Apr 2012
     by Tom Igoe


    #include <SPI.h>
    #include <EthernetV2_0.h>

    // Enter a MAC address for your controller below.
    // Newer Ethernet shields have a MAC address printed on a sticker on         the shield
    byte mac[] = {  
      /*MAC Address here*/ };

    // Initialize the Ethernet client library
    // with the IP address and port of the server 
    // that you want to connect to (port 80 is default for HTTP):
    EthernetClient client;

    void setup() {
     // Open serial communications and wait for port to open:
      Serial.println("Baud rate set!");

      // start the Ethernet connection:
      if (Ethernet.begin(mac) == 0) {
        Serial.println("Failed to configure Ethernet using DHCP");
        // no point in carrying on, so do nothing forevermore:
      // print your local IP address:
      Serial.print("My IP address: ");
      for (byte thisByte = 0; thisByte < 4; thisByte++) {
        // print the value of each byte of the IP address:
        Serial.print(Ethernet.localIP()[thisByte], DEC);

    void loop() {

  • run the WebClient example sketch
    – jsotola
    Oct 19, 2018 at 2:34

1 Answer 1


Don't use the MAC address of your computer read from ipconfig output. It creates a conflict on LAN. Use the MAC address from examples.

To troubleshoot Ethernet shield, use the Ethernet library newest version 2.00. It supports W5100, W5200 and W5500 and has better diagnostic in examples.

And to troubleshoot, always connect the LAN cable to router or switch, not to computer, because direct connection to computer requires manual setup of addresses (no DHCP).

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