与 localhost:30000 的连接被拒绝，即使我知道它正在监听

Question

我正在使用 C 和 Winsock2 设置一个简单的服务器和客户端应用程序。有一天我设法让它工作，但第二天，它一直给我错误 10061（连接被拒绝）。我没有更改我的安全设置或我认为相关的任何内容。

我可以通过在地址栏中键入 localhost:30000 使用 Web 浏览器连接到服务器。我查看了我的代码，将其与官方 Winsock 教程进行了比较，但似乎没有任何效果。

由于服务器似乎完美无缺，这里是客户端代码，直到它失败的部分：

#if defined __WIN32__ || defined _WIN32 || defined WIN32
// define WINVER for MinGW
#ifndef WINVER
#define WINVER 0x0501
#endif
#include <winsock2.h>
#include <ws2tcpip.h>
#else
//(this will be for Linux code that I haven't implemented yet)
#endif
#include <stdio.h>
#include <sys/types.h>
#include <process.h>
#define PORTNUM "30000"
#define BUFLEN 512

int main(int argc, char *argv[]) {
    WSADATA wsaData;
    // Create new SOCKET object
    SOCKET ConnectSocket = INVALID_SOCKET;
    // Create socket for client
    struct addrinfo *result = NULL,
                    *ptr = NULL,
                    hints;
    // Initialize Winsock
    int iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
    if (iResult != 0) {
        fprintf(stderr, "WSAStartup failed: %d\n", iResult);
        exit(1);
    }

    ZeroMemory( &hints, sizeof(hints) );
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;

    // Resolve the server address and port
    iResult = getaddrinfo(argv[1], PORTNUM, &hints, &result);
    if (iResult != 0) {
        printf("getaddrinfo failed: %d\n", iResult);
        WSACleanup();
        return 1;
    }
    // Attempt to connect to the first address returned by
    // the call to getaddrinfo
    ptr=result;
    // Create a SOCKET for connecting to server
    ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype,
        ptr->ai_protocol);
    if (ConnectSocket == INVALID_SOCKET) {
        printf("Error at socket(): %ld\n", WSAGetLastError());
        freeaddrinfo(result);
        WSACleanup();
        return 1;
    }

    // Connect to server.
    iResult = connect(ConnectSocket, ptr->ai_addr, (int)ptr->ai_addrlen);
    if (iResult == SOCKET_ERROR) {
        printf("Error at connect(): %ld\n", WSAGetLastError());
        closesocket(ConnectSocket);
        ConnectSocket = INVALID_SOCKET;
        scanf("%s", NULL);
    }
// ...
}

Answer 1

我不确定这是否能解决您的问题，但请对以下部分进行一些小改动：

    ZeroMemory( &hints, sizeof(hints) );
    hints.ai_family = AF_INET; // <-- Here
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;

我认为这可能是原因，因为我在 MSDN 中找到了这句话：

The values currently supported are AF_INET or AF_INET6, which are the Internet address family formats for IPv4 and IPv6. Other options for address family (AF_NETBIOS for use with NetBIOS, for example) are supported if a Windows Sockets service provider for the address family is installed [link].

也许这部分会造成您的问题。

与 localhost:30000 的连接被拒绝，即使我知道它正在监听

Connection to localhost:30000 refused even though I know it's listening

c

sockets

winsock2