File content as of revision 1:52ba06578336:

#include "mbed.h"
#include "EthernetInterface.h"
#include "gets.h"

 
#define MBED_DEV_IP       "192.168.0.52"
#define MBED_DEV_MASK   "255.255.255.0"
#define MBED_DEV_GW      "0.0.0.0"
#define ECHO_SERVER_PORT   80
// 5000

int main (void) {
    
    
    EthernetInterface eth;
    eth.init(MBED_DEV_IP, MBED_DEV_MASK, MBED_DEV_GW); //Assign a device ip, mask and gateway
   // eth.init();
    eth.connect();
    printf("IP Address is %s\n", eth.getIPAddress()); //"192.168.0.52"
    
    TCPSocketServer server;
    server.bind(ECHO_SERVER_PORT);
    server.listen();

    while (true) {
        printf("\nWait for new connection...\n");
        TCPSocketConnection client;
        server.accept(client);
        client.set_blocking(false, 1500); // Timeout after (1.5)s
        
        printf("Connection from: %s\n", client.get_address());
        char buffer[256];
        while (true) {
            int n = client.receive(buffer, sizeof(buffer));
            if(n>0){
            getsth(buffer[0], eth, client);
            n=0;
        }
     }
    }
}