till now, i am able to operate ethernet board from web browser of same network.
i am using dynamic dns network service and operating the network of my laptop and arduino from a router(iball DATON) which is connected to modem.
can anyone plz guide me to use ethernet shield from different network? 
some one suggested me of port forwarding, checking firewall settings and pointing traffic to mac address of arduino
but, i am not that expert in networking. 
what should i do? and how? :smiley-roll :~
thank you very much.
but the version of router i am using is not specified in this site. but they told that they are going to fix that soon.
till then, i am trying myself. 8)
can you please give me any reference or the sketch for ethernet shield to check its working from separate network.
i googled it but i am not sure whether to include subnet mask, gateway in the sketch or not. 
this is the sketch i uploaded -
#include <SPI.h>
#include <Ethernet.h>
#include <string.h>
byte mac[] = {0x00, 0x1E, 0x2A, 0x77, 0x24, 0x02 };
byte ip[] = {192,168,0,3 };
byte gateway[] = {192, 168, 0, 1 };
byte subnet[] = {255, 255, 255, 0 };
EthernetServer server(80); // Port 80 is http.
//-- Commands and parameters (sent by browser) --
char cmd[15]; // Nothing magical about 15, increase these if you need longer commands/parameters
char param1[15];
char param2[15];
//-- Sample Ports ---
void SetupSamplePorts()
{
// To illustrate how to use this, I have an LED and a Potentiometer.
// The 10K potentiometer left lead is connected to GND, right lead to +5V, and middle lead to Analog 0.
// The LED cathode is on digital pin 7 and anode is on pin 8.
pinMode(7,OUTPUT); digitalWrite(7,LOW); // I use this pin as GND for the LED.
pinMode(8,OUTPUT); // Sample output, unable to use built-in LED at pin 13 because Ethernet Shield uses pins 10,11,12,13.
}
void setup()
{
Ethernet.begin(mac, ip);
server.begin();
Serial.begin(57600);
SetupSamplePorts();
}
#define bufferMax 128
int bufferSize;
char buffer[bufferMax];
void loop()
{
EthernetClient client = server.available();
if (client)
{
WaitForRequest(client);
ParseReceivedRequest();
PerformRequestedCommands();
client.stop();
}
}
void WaitForRequest(EthernetClient client) // Sets buffer[] and bufferSize
{
bufferSize = 0;
while (client.connected()) {
if (client.available()) {
char c = client.read();
if (c == '\n')
break;
else
if (bufferSize < bufferMax)
buffer[bufferSize++] = c;
else
break;
}
}
PrintNumber("bufferSize", bufferSize);
}
void ParseReceivedRequest()
{
Serial.println("in ParseReceivedRequest");
Serial.println(buffer);
//Received buffer contains "GET /cmd/param1/param2 HTTP/1.1". Break it up.
char* slash1;
char* slash2;
char* slash3;
char* space2;
slash1 = strstr(buffer, "/") + 1; // Look for first slash
slash2 = strstr(slash1, "/") + 1; // second slash
slash3 = strstr(slash2, "/") + 1; // third slash
space2 = strstr(slash2, " ") + 1; // space after second slash (in case there is no third slash)
if (slash3 > space2) slash3=slash2;
PrintString("slash1",slash1);
PrintString("slash2",slash2);
PrintString("slash3",slash3);
PrintString("space2",space2);
// strncpy does not automatically add terminating zero, but strncat does! So start with blank string and concatenate.
cmd[0] = 0;
param1[0] = 0;
param2[0] = 0;
strncat(cmd, slash1, slash2-slash1-1);
strncat(param1, slash2, slash3-slash2-1);
strncat(param2, slash3, space2-slash3-1);
PrintString("cmd",cmd);
PrintString("param1",param1);
PrintString("param2",param2);
}
void PerformRequestedCommands()
{
if ( strcmp(cmd,"digitalWrite") == 0 ) RemoteDigitalWrite();
if ( strcmp(cmd,"analogRead") == 0 ) RemoteAnalogRead();
}
void RemoteDigitalWrite()
{
int ledPin = param1[0] - '0'; // Param1 should be one digit port
int ledState = param2[0] - '0'; // Param2 should be either 1 or 0
digitalWrite(ledPin, ledState);
//-- Send response back to browser --
server.print("D");
server.print(ledPin, DEC);
server.print(" is ");
server.print( (ledState==1) ? "ON" : "off" );
//-- Send debug message to serial port --
Serial.println("RemoteDigitalWrite");
PrintNumber("ledPin", ledPin);
PrintNumber("ledState", ledState);
}
void RemoteAnalogRead()
{
// If desired, use more server.print() to send http header instead of just sending the analog value.
int analogPin = param1[0] - '0'; // Param1 should be one digit analog port
int analogValue = analogRead(analogPin);
//-- Send response back to browser --
server.print("A");
server.print(analogPin, DEC);
server.print(" is ");
server.print(analogValue,DEC);
//-- Send debug message to serial port --
Serial.println("RemoteAnalogRead");
PrintNumber("analogPin", analogPin);
PrintNumber("analogValue", analogValue);
}
void PrintString(char* label, char* str)
{
Serial.print(label);
Serial.print("=");
Serial.println(str);
}
void PrintNumber(char* label, int number)
{
Serial.print(label);
Serial.print("=");
Serial.println(number, DEC);
}
is there need of static ip and viop?
or dynamic dns service is sufficient?
You don't need a static IP - dyndns takes care of this part for you. You do however have to configure your router to pass traffic on your chosen port (80 in the simple case) to the arduino.