socket client連接不上

#c++ #socket

jimmy940808 2022-12-09 23:01:03 ‧ 1364 瀏覽

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我用c++(socket)創了server和client兩個檔案, 在自己電腦裡能接收到client的回應
畢竟是自己的電腦, 但是把client傳給別人後卻收不到回應, 防火牆都有關
請問是為甚麼呢?

**server

#include <stdio.h>
#include <WinSock2.h>
#include <iostream>
#pragma comment (lib, "ws2_32.lib")
using namespace std;

int main()
{
	//初始化網路
	WSADATA wd;
	WSAStartup(MAKEWORD(2, 2), &wd);

	//創建套接字
	SOCKET sockServ = socket(AF_INET, SOCK_STREAM, 0); //ipv4
	SOCKADDR_IN addrServ;
	addrServ.sin_family = AF_INET;
	addrServ.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
	addrServ.sin_port = htons(10010);

	bind(sockServ, (SOCKADDR*)&addrServ, sizeof(SOCKADDR));

	//監聽
	listen(sockServ, 5);

	while (true)
	{
		//接受客戶端請求
		SOCKADDR_IN addrClient;
		int length = sizeof(addrClient);
		SOCKET sockColn = accept(sockServ, (SOCKADDR*)&addrClient, &length);
		cout << inet_ntoa(addrClient.sin_addr)<<endl;
		cout<<addrClient.sin_port;
	}

	WSACleanup();

	return 0;
}

**client

#include <stdio.h>
#include <WinSock2.h>

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

int main()
{
	//初始化網路
	WSADATA wd;
	WSAStartup(MAKEWORD(2, 2), &wd);

	//創建套接字
	SOCKET sockClien = socket(AF_INET, SOCK_STREAM, 0);
	SOCKADDR_IN addrServ;
	addrServ.sin_family = AF_INET;
    
    //server電腦IP: 192.168.77.195
	addrServ.sin_addr.S_un.S_addr = inet_addr("192.168.77.195");  
    
	addrServ.sin_port = htons(10010);

	connect(sockClien, (SOCKADDR*)&addrServ, sizeof(SOCKADDR));

	

	WSACleanup();

	return 0;
}

re.Zero iT邦研究生 5 級 ‧ 2022-12-10 16:36:36 檢舉

我是認為，你先把程式的除錯/錯誤處理基礎功能寫好，不然很難找問題。
例如在[ https://learn.microsoft.com/zh-tw/windows/win32/api/winsock2/nf-winsock2-wsaaccept ]內有敘述：「如果沒有發生錯誤， WSAAccept 會傳回 SOCKET 類型的值，這是接受之通訊端的描述項。否則，會傳回INVALID_SOCKET的值，並呼叫 WSAGetLastError來擷取特定的錯誤碼。」
後續範例也有 WSAAccept 異常時處理 WSAAccept 傳回值的基礎用法。

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2 個回答

JamesDoge

iT邦高手 1 級 ‧ 2022-12-20 04:29:06

可以先把程式碼中加入除錯/錯誤處理基礎功能
透過處理 WSAAccept 傳回值擷取errorCode

**server

#include <stdio.h>
#include <WinSock2.h>
#include <iostream>
#pragma comment (lib, "ws2_32.lib")
using namespace std;

int main()
{
//初始化網路
WSADATA wd;
WSAStartup(MAKEWORD(2, 2), &wd);
//創建套接字
SOCKET sockServ = socket(AF_INET, SOCK_STREAM, 0); //ipv4
SOCKADDR_IN addrServ;
addrServ.sin_family = AF_INET;
addrServ.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
addrServ.sin_port = htons(10010);

bind(sockServ, (SOCKADDR*)&addrServ, sizeof(SOCKADDR));

//監聽
listen(sockServ, 5);

while (true)
{
	//接受客戶端請求
	SOCKADDR_IN addrClient;
	int length = sizeof(addrClient);
	SOCKET sockColn = WSAAccept(sockServ, (SOCKADDR*)&addrClient, &length, NULL, NULL);
	if (sockColn == INVALID_SOCKET)
	{
		//處理 WSAAccept 傳回值的基礎用法
		int errorCode = WSAGetLastError();
		cout << "Error occurred during WSAAccept: " << errorCode << endl;
	}
	else
	{
		cout << inet_ntoa(addrClient.sin_addr)<<endl;
		cout<<addrClient.sin_port;
	}
}

WSACleanup();

return 0;

}

**client

#include <stdio.h>
#include <WinSock2.h>

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

int main()
{
//初始化網路
WSADATA wd;
WSAStartup(MAKEWORD(2, 2), &wd);
//創建套接字
SOCKET sockClien = socket(AF_INET, SOCK_STREAM, 0);
SOCKADDR_IN addrServ;
addrServ.sin_family = AF_INET;

//server電腦IP: 192.168.77.195
addrServ.sin_addr.S_un.S_addr = inet_addr("192.168.77.195");  

addrServ.sin_port = htons(10010);

if(connect(sockClien, (SOCKADDR*)&addrServ, sizeof(SOCKADDR)) == INVALID_SOCKET)
{
    printf("Connect error: %d\n", WSAGetLastError());
    WSACleanup();
    return -1;
}



WSACleanup();

return 0;

}