Question

我正在编写代码来发现网络上的设备，这只是其中的一部分。

我正在尝试通过在端口80上与主机建立套接字连接来发现主机。

它在端口80上的某些主机上连接良好，因为设备正在侦听端口80.有时 connect 函数返回错误WSACONNECTIONREFUSED，因为没有运行Web服务在主持人身上。

令人惊讶的是，当我尝试在无效的IP地址上建立套接字连接时，我得WSACONNECTIONREFUSED而不是WSAETIMEDOUT。

我用谷歌搜索并发现防病毒软件和防火墙可以导致问题，我已经在扫描机上禁用了这两个但没有运气可能导致问题？

我已经发布了以下代码：

#ifndef UNICODE
#define UNICODE
#endif

#define WIN32_LEAN_AND_MEAN

#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>

#pragma comment(lib, "ws2_32.lib")

int main()
{
  WSADATA wsaData;
  int iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
  if (iResult != NO_ERROR)
  {
    wprintf(L"WSAStartup function failed with error: %d\n", iResult);
    return 1;
  }
  SOCKET ConnectSocket;
  ConnectSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

  if (ConnectSocket == INVALID_SOCKET)
  {
    wprintf(L"socket function failed with error: %ld\n", WSAGetLastError());
    WSACleanup();
    return 1;
  }
  sockaddr_in clientService;
  clientService.sin_family = AF_INET;

  clientService.sin_addr.s_addr = inet_addr("192.168.4.28"); //No Host by this ip   address 

  clientService.sin_port = htons(80); //Port is 80 

  iResult = connect(ConnectSocket, (SOCKADDR *) &clientService,
      sizeof(clientService));

  printf("The socket connect return status : %d ", iResult);
  if (iResult == SOCKET_ERROR)
  {

    wprintf(L"connect function failed with error: %ld\n", WSAGetLastError());

    iResult = closesocket(ConnectSocket);
    if (iResult == SOCKET_ERROR)
      wprintf(L"closesocket function failed with error: %ld\n",
          WSAGetLastError());
    WSACleanup();
    return 1;
  }

  wprintf(L"Connected to server.\n");

  iResult = closesocket(ConnectSocket);
  if (iResult == SOCKET_ERROR)
  {
    printf("\n socket Connection failed ");
    WSACleanup();
    return 1;
  }

  WSACleanup();
  return 0;
}

即使主机不存在，WSA Connection仍然拒绝

0 个答案: