whats the difference between two sketch arduino nano ethernet

i upload the default Ethernet/WebServer example, but it never takes ip. then i changed the library and upload UIPEthernet then it works fine. here is the codes for UIPEthernet and see attached UIPEthernet_library.zip

whats the gap in the default ethernet webserver sketch? How can we modify the default webserver.ino?

// UIP is a proper library for Arduino Nano Ethernet shield
// NOTE: UIPEthernet library is not needed if you are using Arduino UNO/Duemilanove/Mega/etc.
// UIPEthernet library is used for Arduino Nano Ethernet Shield

#include <UIPEthernet.h> // Used for Ethernet

byte mac = { 0x90, 0xA2, 0xDA, 0x0D, 0x78, 0xEE };
IPAddress ip(192, 168, 1, 115);
EthernetServer server(80);

void setup() {

// start the Ethernet connection and the server:
Ethernet.begin(mac, ip);

Serial.print("IP Address: ");

void loop() {
// listen for incoming clients
EthernetClient client = server.available();

if (client)
Serial.println("-> New Connection");

// an http request ends with a blank line
boolean currentLineIsBlank = true;

while (client.connected())
if (client.available())
char c = client.read();

// if you’ve gotten to the end of the line (received a newline
// character) and the line is blank, the http request has ended,
// so you can send a reply
if (c == ‘\n’ && currentLineIsBlank)
client.println(“Hello World!

Hello World!


if (c == ‘\n’) {
// you’re starting a new line
currentLineIsBlank = true;
else if (c != ‘\r’)
// you’ve gotten a character on the current line
currentLineIsBlank = false;

// give the web browser time to receive the data

// close the connection:
Serial.println(" Disconnected\n");

UIPEthernet_library.zip (101 KB)