Added DHCP address printer and DNS-based web client, based on Adrian McEwen's additions to the Ethernet library

Author: tigoe

libraries/Ethernet/examples/DhcpAddressPrinter/DhcpAddressPrinter.pde

@@ -0,0 +1,53 @@
+/*
+  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. 
+ 
+ Circuit:
+ * Ethernet shield attached to pins 10, 11, 12, 13
+ 
+ created 12 April 2011
+ by Tom Igoe
+ 
+ */
+
+#include <SPI.h>
+#include <Ethernet.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[] = {  
+  0x00, 0xAA, 0xBB, 0xCC, 0xDE, 0x02 };
+
+// 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):
+Client client;
+
+void setup() {
+  // start the serial library:
+  Serial.begin(9600);
+  // 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:
+    for(;;)
+      ;
+  }
+  // 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);
+    Serial.print("."); 
+  }
+  Serial.println();
+}
+
+void loop() {
+
+}
+
+

libraries/Ethernet/examples/DnsWebClient/DnsWebClient.pde

@@ -0,0 +1,76 @@
+/*
+  DNS and DHCP-based Web client
+ 
+ This sketch connects to a website (http://www.google.com)
+ using an Arduino Wiznet Ethernet shield. 
+ 
+ Circuit:
+ * Ethernet shield attached to pins 10, 11, 12, 13
+ 
+ created 18 Dec 2009
+ by David A. Mellis
+ modified 12 April 2011
+ by Tom Igoe, based on work by Adrian McEwen
+ 
+ */
+
+#include <SPI.h>
+#include <Ethernet.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[] = {  0x00, 0xAA, 0xBB, 0xCC, 0xDE, 0x02 };
+char serverName[] = "www.google.com";
+
+// 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):
+Client client;
+
+void setup() {
+  // start the serial library:
+  Serial.begin(9600);
+  // 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:
+    while(true);
+  }
+  // give the Ethernet shield a second to initialize:
+  delay(1000);
+  Serial.println("connecting...");
+
+  // if you get a connection, report back via serial:
+  
+  if (client.connect(serverName, 80)) {
+    Serial.println("connected");
+    // Make a HTTP request:
+    client.println("GET /search?q=arduino HTTP/1.0");
+    client.println();
+  } 
+  else {
+    // kf you didn't get a connection to the server:
+    Serial.println("connection failed");
+  }
+}
+
+void loop()
+{
+  // if there are incoming bytes available 
+  // from the server, read them and print them:
+  if (client.available()) {
+    char c = client.read();
+    Serial.print(c);
+  }
+
+  // if the server's disconnected, stop the client:
+  if (!client.connected()) {
+    Serial.println();
+    Serial.println("disconnecting.");
+    client.stop();
+
+    // do nothing forevermore:
+    while(true);
+  }
+}
+