ESP32 + W5500 Ethernet Webserver Example not working

Hello, I want to use the W5500 Ethernet Board (SPI) in combination with a ESP32 Dev Board. I know that this is a known issue. I cant get it to compile, i tried a couple of libs and methodes, but it wont work:

cannot declare variable 'server' to be of abstract type 'EthernetServer'

I just want to get the Webserver Example to work, can anyone help me with that? :cry:

Do you think it might help if you provided full details of the hardware and your code ?

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  Web Server

 A simple web server that shows the value of the analog input pins.
 using an Arduino Wiznet Ethernet shield.

 * Ethernet shield attached to pins 10, 11, 12, 13
 * Analog inputs attached to pins A0 through A5 (optional)

 created 18 Dec 2009
 by David A. Mellis
 modified 9 Apr 2012
 by Tom Igoe
 modified 02 Sept 2015
 by Arturo Guadalupi

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

// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network:
byte mac[] = {
  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED
IPAddress ip(192, 168, 1, 177);

// Initialize the Ethernet server library
// with the IP address and port you want to use
// (port 80 is default for HTTP):
EthernetServer server(80);

void setup() {
  // You can use Ethernet.init(pin) to configure the CS pin
  //Ethernet.init(10);  // Most Arduino shields
  //Ethernet.init(5);   // MKR ETH shield
  //Ethernet.init(0);   // Teensy 2.0
  //Ethernet.init(20);  // Teensy++ 2.0
  //Ethernet.init(15);  // ESP8266 with Adafruit Featherwing Ethernet
  //Ethernet.init(33);  // ESP32 with Adafruit Featherwing Ethernet

  // Open serial communications and wait for port to open:
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  Serial.println("Ethernet WebServer Example");

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

  // Check for Ethernet hardware present
  if (Ethernet.hardwareStatus() == EthernetNoHardware) {
    Serial.println("Ethernet shield was not found.  Sorry, can't run without hardware. :(");
    while (true) {
      delay(1); // do nothing, no point running without Ethernet hardware
  if (Ethernet.linkStatus() == LinkOFF) {
    Serial.println("Ethernet cable is not connected.");

  // start the server
  Serial.print("server is at ");

void loop() {
  // listen for incoming clients
  EthernetClient client = server.available();
  if (client) {
    Serial.println("new client");
    // an http request ends with a blank line
    boolean currentLineIsBlank = true;
    while (client.connected()) {
      if (client.available()) {
        char c =;
        // 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) {
          // send a standard http response header
          client.println("HTTP/1.1 200 OK");
          client.println("Content-Type: text/html");
          client.println("Connection: close");  // the connection will be closed after completion of the response
          client.println("Refresh: 5");  // refresh the page automatically every 5 sec
          client.println("<!DOCTYPE HTML>");
          // output the value of each analog input pin
          for (int analogChannel = 0; analogChannel < 6; analogChannel++) {
            int sensorReading = analogRead(analogChannel);
            client.print("analog input ");
            client.print(" is ");
        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("client disconnected");

Thanks for your quick response, this is the Example, but i tried many different approaches.
Im using a board like this: W5500 Ethernet netzwerk modul hardware TCP / IP 51 / STM32 mikrocontroller programm über W5100 A32|tcp ip|programming microcontrollers - AliExpress

I did a google-search and found this site

though I don't know igf this solves your problems.
As an ESP32 has WLAN on board would these be an alternative option?

best regards Stefan

Hello Stefan, I already tried this and it was working just fine but then I tried to modify that code to work as Webserver, but the same issue occurred...

does someone have another idea to solve this problem?

I know that this is a known issue

Where did you see this ?

I ment that im not the only one with this problem :confused:

I ment that im not the only one with this problem :confused:

I give up

And i found the solution !!! Use the Ethernet2 Lib, but NOT from the LibManager. Use this one and copy it yourself into the Lib folder :slight_smile:

You can also try this EthernetWebServer Library, especially these examples written for ESP32/ESP8266

  1. WebClientRepeating_ESP
  2. WebClient_ESP

and also

Libraries Patches

  1. To fix ESP32 compile error, just copy the following file into the ESP32 cores/esp32 directory (e.g. ./arduino-1.8.12/hardware/espressif/cores/esp32) to overwrite the old file:

And i found the solution !!! Use the Ethernet2 Lib, but NOT from the LibManager. Use this one and copy it yourself into the Lib folder :slight_smile:

That worked for me too. Thank you very much! :smiley:

And i found the solution !!! Use the Ethernet2 Lib, but NOT from the LibManager. Use this one and copy it yourself into the Lib folder :slight_smile:

can you share your program at

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