Control arduino ethernet whit C++ socket code

I apologize for my bad English.

I upload my arduino ethernet with this sketch:

#include <Ethernet.h>

// the media access control (ethernet hardware) address for the shield:
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };  
//the IP address for the shield:
byte ip[] = { 10, 0, 0, 177 };    
// the router's gateway address:
byte gateway[] = { 10, 0, 0, 1 };
// the subnet:
byte subnet[] = { 255, 255, 0, 0 };

// telnet defaults to port 23
Server server = Server(23);

void setup()
  // initialize the ethernet device
  Ethernet.begin(mac, ip, gateway, subnet);

  // start listening for clients

void loop()
  // if an incoming client connects, there will be bytes available to read:
  Client client = server.available();
  if (client == true) {
    // read bytes from the incoming client and write them back
    // to any clients connected to the server:

From my PC i compile this C++ code with no errors:

#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <stdio.h>
#include <netinet/in.h>
#include <resolv.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>

int main(int argv, char** argc){

    int host_port= 23;
    char* host_name="";

    struct sockaddr_in my_addr;

    char buffer[1024];
    int bytecount;
    int buffer_len=0;

    int hsock;
    int * p_int;
    int err;

    hsock = socket(AF_INET, SOCK_STREAM, 0);
    if(hsock == -1){
        printf("Error initializing socket %d\n",errno);
        goto FINISH;

    p_int = (int*)malloc(sizeof(int));
    *p_int = 1;

    if( (setsockopt(hsock, SOL_SOCKET, SO_REUSEADDR, (char*)p_int, sizeof(int)) == -1 )||
        (setsockopt(hsock, SOL_SOCKET, SO_KEEPALIVE, (char*)p_int, sizeof(int)) == -1 ) ){
        printf("Error setting options %d\n",errno);
        goto FINISH;

    my_addr.sin_family = AF_INET ;
    my_addr.sin_port = htons(host_port);

    memset(&(my_addr.sin_zero), 0, 8);
    my_addr.sin_addr.s_addr = inet_addr(host_name);

    if( connect( hsock, (struct sockaddr*)&my_addr, sizeof(my_addr)) == -1 ){
        if((err = errno) != EINPROGRESS){
            fprintf(stderr, "Error connecting socket %d\n", errno);
            goto FINISH;

    //Now lets do the client related stuff

    buffer_len = 1024;

    memset(buffer, '\0', buffer_len);

    printf("Enter some text to send to the server (press enter)\n");
    fgets(buffer, 1024, stdin);

    if( (bytecount=send(hsock, buffer, strlen(buffer),0))== -1){
        fprintf(stderr, "Error sending data %d\n", errno);
        goto FINISH;
    printf("Sent bytes %d\n", bytecount);

    if((bytecount = recv(hsock, buffer, buffer_len, 0))== -1){
        fprintf(stderr, "Error receiving data %d\n", errno);
        goto FINISH;
    printf("Recieved bytes %d\nReceived string \"%s\"\n", bytecount, buffer);



When i try to connect to my arduino i have success, but when i send data it return a strange response.

See the output beelowe:

Enter some text to send to the server (press enter)
Sent bytes 1
Recieved bytes 1024
Received string "???????????????????????????????????????????????????????????????????????????????????????????????????.........and more???

Why i don't get an "a" character?

Thanks in advance

  if (client == true) {
    // read bytes from the incoming client and write them back
    // to any clients connected to the server:

A client connection was created. That does not mean that the client has received any data. You read that data anyway, and send it back out.

The Client class has two methods, connected() and available() that you need to integrate into your Arduino code.