CODEWITHSUNDEEP
cwindowssockets
Min Kim
Min Kim

Reputation: 113

Port is listening but "No connection could be made because the target machine actively refused it "

I have a server/client program. The code worked just a few minutes ago. After running several times, it suddenly gives error 10061. I use "netstat -a -b" to check if the server port is occupied. But I get this which seems OK:

[System]
TCP     0.0.0.0:6666    Listening

Client code:

SOCKET sendrecv;
sendrecv = InitClientSocket(serverIP, 6666);

ps. ping serverIP also works. Firewall is off too. 

SOCKET InitClientSocket(char *pHost, int iPort){
    struct sockaddr_in saClient;
    struct hostent *pHostinfo;
    SOCKET sock;

    WORD version;
    WSADATA WSAData;
    version=MAKEWORD(1,1);
    WSAStartup(version, &WSAData);

    sock=socket(AF_INET,SOCK_STREAM,0);
    if (sock ==SOCKET_ERROR){
        closesocket(sock);
        return 0;
    }

    pHostinfo=gethostbyname(pHost);
    if (pHostinfo==NULL){
        closesocket(sock);
        return 0;
    }

    saClient.sin_family=AF_INET;
    saClient.sin_addr=*((struct in_addr *)pHostinfo->h_addr);
    saClient.sin_port=htons(iPort);

    int nConnect=0;
    nConnect=connect(sock,(struct sockaddr *)&saClient, sizeof(saClient));
    if(nConnect == SOCKET_ERROR)    //Here comes the error 10061
    {
        int err = WSAGetLastError();
        closesocket(sock);
        return 0;
    }

    return sock;
}

New Edit- Here is part of Server code :

SOCKET sock, sendrecv;
struct sockaddr_in sock_addr,sendrecv_addr;
WSADATA data;

WSAStartup( MAKEWORD(2,0), &data);
sock = WSASocket (AF_INET, SOCK_STREAM, 0, 0, 0, 0);

int nREUSEADDR = 1;
setsockopt(sock,SOL_SOCKET,SO_REUSEADDR,(const char*)&nREUSEADDR,sizeof(int)); 

sock_addr.sin_family=PF_INET;
sock_addr.sin_port=htons(6666);         
sock_addr.sin_addr.s_addr=INADDR_ANY;
bind(sock,(struct sockaddr*)&sock_addr,sizeof(struct sockaddr_in));
listen(sock,1);
int lun = sizeof (struct sockaddr);
sendrecv = accept(sock,(struct sockaddr*)&sendrecv_addr,&lun);

linger m_sLinger;
m_sLinger.l_onoff = 1; 
m_sLinger.l_linger = 0; 
setsockopt(sendrecv,SOL_SOCKET,SO_LINGER,(const char*)&m_sLinger,sizeof(linger));

Upvotes: 1

Views: 475

Answers (1)

user207421
user207421

Reputation: 310860

A Windows server will start refusing connections once its listen backlog queue fills. Your server isn't accepting fast enough, or at all.

Upvotes: 1

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