服务器和客户端都在PC上运行.客户端可以使用PC的IP连接到服务器

我是网络编程的新手，所以这让我困惑了几天。

我写了2个应用程序：一个是服务器，一个是客户端。

我希望他们做的是：当我为客户端提供IP地址时，客户端将使用提供的IP连接到机器上的服务器。

我通过在我的PC上打开服务器和客户端来测试它，并在循环返回地址(127.0.0.1(中输入。客户端连接到服务器罚款(我什至可以彼此发送短信(。

所以我尝试了进一步。我搜索了我的IP(113.20.98.124(，然后将其喂给我的客户。我希望客户也将连接到服务器，但这没有发生。客户终止并说连接定时(WSAETIMEDOUT 10060(。

我想问的是：为什么我不能使用IP告诉客户端连接到我的服务器？那是什么吗？

这是我的服务器和客户端的代码(如果我做错了什么(：

(我在Windows上使用VS2017编码(

客户端：

#include <iostream>
#include <WS2tcpip.h>
#include <winsock2.h>
#include <string>

//The port which will be used to connect to server
#define PORT "7777"

std::string getIPAddress()
{
    std::string out;
    std::cout << "IP/Domain to connect to: ";
    std::cin >> out;
    std::cin.ignore();
    return out;
}
//Print out error code and exit the program in case something goes wrong
void failure_exit(std::string message, int exitVal)
{
    std::cerr << message
        << " Error code: " << WSAGetLastError() << " n";
    WSACleanup();
    std::cin.get();
    exit(exitVal);
}

int main(int argc, char *argv[])
{
    WSADATA wsaData;
    if (WSAStartup(MAKEWORD(1, 0), &wsaData) != 0)
        failure_exit("WSAStartup failed!", 1);

    addrinfo hints;
    memset(&hints, 0, sizeof(hints));
    hints.ai_family = AF_UNSPEC; //AF_INET or AF_INET6 are totally fine
    hints.ai_socktype = SOCK_STREAM; //TCP connection

    //Get the IP from user
    std::string IPconnect = getIPAddress();

    //A pointer to a linked list of juicy results we can use 
    addrinfo *result(nullptr);
    //Prepare the addrinfo for a connecting socket
    if (getaddrinfo(IPconnect.c_str(), PORT, &hints, &result) != 0)
        failure_exit("getaddrinfo failed!", 2);

/*PREPARING A SOCKET*/
    SOCKET sockfd;
    //A pointer to one of the addrinfos from result, which is a usable one
    //'chosen' will also be used in connect() call
    addrinfo *chosen(result);
    //Run through the results got from getaddrinfo and pick the first usable addrinfo
    for (; chosen != nullptr; chosen = chosen->ai_next)
    {
        //see if sockfd is legit to use
        if ((sockfd = socket(chosen->ai_family, chosen->ai_socktype, chosen->ai_protocol)) != -1)
            break;
    }
    freeaddrinfo(result);
    //Socket preparation failed
    if (sockfd<=0)
        failure_exit("Socket preparation failed!", 3);

/*CONNECT!*/
    std::cout << "Connecting... 20 seconds until timed out.n";
    if (connect(sockfd, chosen->ai_addr, chosen->ai_addrlen) != 0)
        failure_exit("Failed to connect!", 4);
    std::cout << "Connected!n";
    WSACleanup();
    std::cin.get();
    return 0;
}

服务器：

#include <iostream>
#include <WS2tcpip.h>
#include <winsock2.h>
#include <string>

//The port which this server will be using 
//to listen to incoming connections
#define PORT "7777"
//Limits how many pending connections
//can be queued up
#define BACKLOG 10

void failure_exit(std::string message, int exitVal)
{
    std::cerr << message
        << " Error code: " << WSAGetLastError() << " n";
    WSACleanup();
    std::cin.get();
    exit(exitVal);
}

int main(int argc, char* argv[])
{
    WSADATA wsa;
    if (WSAStartup(MAKEWORD(1, 0), &wsa) != 0)
        failure_exit("WSAStartup failed!", 1);

    addrinfo hints;
    memset(&hints, 0, sizeof(hints));
    //IPv4 or IPv6 are both Ok
    hints.ai_family = AF_INET;
    //This addrinfo will be used for binding
    hints.ai_flags = AI_PASSIVE;
    //TCP connection
    hints.ai_socktype = SOCK_STREAM;

    addrinfo *result;
    if (getaddrinfo(NULL, PORT, &hints, &result) != 0)
        failure_exit("getaddrinfo failed!", 3);

//PREPARE A SOCKET
    SOCKET sockfd(0);
    //The usable addrinfo will be pointed to by 'chosen'
    addrinfo *chosen(result);
    //Loop through the results to find a suitable one
    for (; chosen != nullptr; chosen = chosen->ai_next)
    {
        sockfd = socket(chosen->ai_family, chosen->ai_socktype, chosen->ai_protocol);
        //Stop at the first usable
        if (sockfd != -1)
            break;
    }
    freeaddrinfo(result);
    //Check for preparation failure
    if (sockfd <= 0)
        failure_exit("Socket preparation failed!", 4);

    //Bind the socket above to my chosen PORT
    if (bind(sockfd, chosen->ai_addr, chosen->ai_addrlen) == -1)
        failure_exit("Binding failed!", 5);

    //Start listening for incoming connections
    if (listen(sockfd, BACKLOG) == -1)
        failure_exit("Listening failed!", 6);

    //The new socket to be returned by accept()
    SOCKET newfd;
    sockaddr_storage newConnection;
    socklen_t newlength(sizeof(newConnection));
    std::cout << "Anyone?n";
    //Accept a pending connection
    if ((newfd = accept(sockfd, reinterpret_cast<sockaddr*>(&newConnection), &newlength)) == -1)
        failure_exit("Accepting connection failed!", 7);
    std::cout << "Connection accepted!n";
    WSACleanup();
    std::cin.get();
    return 0;
}

我了解的有关网络编程的任何内容均来自http://beej.us/guide/。