user72731: I've mounted an Ethernet Shield on top of an Arduino UNO. The Arduino is connected via usb to my pc and to the network via ethernet through a switch.
I'm running a simplified verison of the WebServer example and the function to Ethernet.begin() always returns EthernetNoHardware.
I've tried different setups changing the ethernet cables and connecting directly to the router. I also tried adding specific ip, gateway and subnet parameters to Ethernet.begin() however the output doesn't change and the server can't be reached:
#include <SPI.h>
#include <Ethernet.h>

byte mac[] = { 0x90, 0xA2, 0xDA, 0x0F, 0xCC, 0x1E }; //mac address on the sticker
IPAddress ip(192, 168, 1, 134);
IPAddress gateway(192,168,1,1);
IPAddress subnet(255,255,255,0);
IPAddress DNSserver(192,168,1,1);
EthernetServer server(80);

void setup() {
  Ethernet.init(10);
  Serial.begin(9600);
  while (!Serial) {
    ;
  }

  Ethernet.begin(mac, ip, gateway, subnet);

  if (Ethernet.hardwareStatus() == EthernetNoHardware) {
    Serial.println("Ethernet shield not found.");
  }


  server.begin();
  Serial.print("server is at ");
  Serial.println(Ethernet.localIP());
} 

output:
Ethernet shield not found.
server is at 192.168.1.134

Any idea on what the issue might be?

user37622: In your sketch DNS IP parameter is missing in Ethernet.begin.
It should be Ethernet.begin(mac, ip, dns, gateway, subnet);

72731: <p>I've mounted an Ethernet Shield on top of an Arduino UNO. The Arduino is connected via usb to my pc and to the network via ethernet through a switch.
I'm running a simplified verison of the WebServer example and the function to Ethernet.begin() always returns EthernetNoHardware.</p>
<p>I've tried different setups changing the ethernet cables and connecting directly to the router. I also tried adding specific ip, gateway and subnet parameters to Ethernet.begin() however the output doesn't change and the server can't be reached:</p>
<pre><code>#include &lt;SPI.h&gt;
#include &lt;Ethernet.h&gt;

byte mac[] = { 0x90, 0xA2, 0xDA, 0x0F, 0xCC, 0x1E }; //mac address on the sticker
IPAddress ip(192, 168, 1, 134);
IPAddress gateway(192,168,1,1);
IPAddress subnet(255,255,255,0);
IPAddress DNSserver(192,168,1,1);
EthernetServer server(80);

void setup() {
  Ethernet.init(10);
  Serial.begin(9600);
  while (!Serial) {
    ;
  }

  Ethernet.begin(mac, ip, gateway, subnet);

  if (Ethernet.hardwareStatus() == EthernetNoHardware) {
    Serial.println(&quot;Ethernet shield not found.&quot;);
  }


  server.begin();
  Serial.print(&quot;server is at &quot;);
  Serial.println(Ethernet.localIP());
} 
</code></pre>
<p>output:</p>
<pre class="lang-none prettyprint-override"><code>Ethernet shield not found.
server is at 192.168.1.134
</code></pre>
<p>Any idea on what the issue might be?</p>
 37622: <p>In your sketch DNS IP parameter is missing in <code>Ethernet.begin</code>.</p>
<p>It should be <code>Ethernet.begin(mac, ip, dns, gateway, subnet);</code></p>
