(SOLVED)Cant get Ethernet WebClientRepeating example working(possibly DNS issue)

I am trying to get arduino to send GET requests (passing sensor data) to a local server. I am using the (almost) un-edited version of WebClientRepeating example as below.

The only error I can think of is incorrect DNS address, but I have no idea what it should actually be.

/*
  Repeating Web client
 
 This sketch connects to a a web server and makes a request
 using a Wiznet Ethernet shield. You can use the Arduino Ethernet shield, or
 the Adafruit Ethernet shield, either one will work, as long as it's got
 a Wiznet Ethernet module on board.
 
 This example uses DNS, by assigning the Ethernet client with a MAC address,
 IP address, and DNS address.
 
 Circuit:
 * Ethernet shield attached to pins 10, 11, 12, 13
 
 created 19 Apr 2012
 by Tom Igoe
 
 http://arduino.cc/en/Tutorial/WebClientRepeating
 This code is in the public domain.
 
 */

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

// assign a MAC address for the ethernet controller.
// fill in your address here:
byte mac[] = { 
  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED};
// fill in an available IP address on your network here,
// for manual configuration:
IPAddress ip(192,168,0,90);

// fill in your Domain Name Server address here:
IPAddress myDns(192,168,0,90);

// initialize the library instance:
EthernetClient client;

char server[] = "www.arduino.cc";

unsigned long lastConnectionTime = 0;           // last time you connected to the server, in milliseconds
boolean lastConnected = false;                  // state of the connection last time through the main loop
const unsigned long postingInterval = 60*1000;  // delay between updates, in milliseconds

void setup() {
  // start serial port:
  Serial.begin(9600);
  // give the ethernet module time to boot up:
  delay(1000);
  // start the Ethernet connection using a fixed IP address and DNS server:
  Ethernet.begin(mac, ip, myDns);
  // print the Ethernet board/shield's IP address:
  Serial.print("My IP address: ");
  Serial.println(Ethernet.localIP());
}

void loop() {
  // if there's incoming data from the net connection.
  // send it out the serial port.  This is for debugging
  // purposes only:
  if (client.available()) {
    char c = client.read();
    Serial.print(c);
  }

  // if there's no net connection, but there was one last time
  // through the loop, then stop the client:
  if (!client.connected() && lastConnected) {
    Serial.println();
    Serial.println("disconnecting.");
    client.stop();
  }

  // if you're not connected, and ten seconds have passed since
  // your last connection, then connect again and send data:
  if(!client.connected() && (millis() - lastConnectionTime > postingInterval)) {
    httpRequest();
    Serial.print("www");
  }
  // store the state of the connection for next time through
  // the loop:
  lastConnected = client.connected();
}

// this method makes a HTTP connection to the server:
void httpRequest() {
  // if there's a successful connection:
  if (client.connect(server, 80)) {
    Serial.println("connecting...");
    // send the HTTP PUT request:
    client.println("GET /latest.txt HTTP/1.1");
    client.println("Host: www.arduino.cc");
    client.println("User-Agent: arduino-ethernet");
    client.println("Connection: close");
    client.println();

    // note the time that the connection was made:
    lastConnectionTime = millis();
  } 
  else {
    // if you couldn't make a connection:
    Serial.println("connection failed");
    Serial.println("disconnecting.");
    client.stop();
  }
}

You DNS server address should be the address of an actual DNS server. Since the Arduino is not a DNS server, it is never correct for it to be the same as the Arduino's own address.

On Windows, you can find the actual address of the local DNS server in the TCP/IP properties under network settings. You can also find it from a command prompt on most platforms by running 'nslookup localhost'.

I am a little confused. Why do I even need a DNS server? I mean I am connecting to a local server by it's IP and not a domain name... And even if it was via a domain, what use would it be if I needed to look up an ip (dns instead of IP behind the domain name).

Client test code that uses the IP address of the server.

//zoomkat 4-04-12
//simple client test
//for use with IDE 1.0
//open serial monitor and send an e to test
//for use with W5100 based ethernet shields
//note that the below bug fix may be required
// http://code.google.com/p/arduino/issues/detail?id=605 
//the arduino lan IP address { 192, 168, 1, 102 } may need 
//to be modified modified to work with your router.

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

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; //physical mac address
byte ip[] = { 192, 168, 1, 102 }; // ip in lan assigned to arduino
//byte gateway[] = { 192, 168, 1, 1 }; // internet access via router
//byte subnet[] = { 255, 255, 255, 0 }; //subnet mask
byte myserver[] = { 208, 104, 2, 86 }; // zoomkat web page server IP address
EthernetClient client;
//////////////////////

void setup(){

  Ethernet.begin(mac, ip);
  //Ethernet.begin(mac, ip, gateway, gateway, subnet);
  Serial.begin(9600); 
  Serial.println("Better client test 4/04/12"); // so I can keep track of what is loaded
  Serial.println("Send an e in serial monitor to test"); // what to do to test
}

void loop(){
  // check for serial input
  if (Serial.available() > 0) //if something in serial buffer
  {
    byte inChar; // sets inChar as a byte
    inChar = Serial.read(); //gets byte from buffer
    if(inChar == 'e') // checks to see byte is an e
    {
      sendGET(); // call sendGET function below when byte is an e
    }
  }  
} 

//////////////////////////

void sendGET() //client function to send/receive GET request data.
{
  if (client.connect(myserver, 80)) {  //starts client connection, checks for connection
    Serial.println("connected");
    client.println("GET /~shb/arduino.txt HTTP/1.0"); //download text
    client.println(); //end of get request
  } 
  else {
    Serial.println("connection failed"); //error message if no client connect
    Serial.println();
  }

  while(client.connected() && !client.available()) delay(1); //waits for data
  while (client.connected() || client.available()) { //connected or data available
    char c = client.read(); //gets byte from ethernet buffer
    Serial.print(c); //prints byte to serial monitor 
  }

  Serial.println();
  Serial.println("disconnecting.");
  Serial.println("==================");
  Serial.println();
  client.stop(); //stop client

}

Thank you for the code sample, I had to edit it quite a bit so that it would send 1 GET request every 1000 ms. Got it working perfectly in the end, Thank you! :slight_smile: