(Ok第二次 l。)

FYI在此有另一个问题:。

http://technet.microsoft.com/en-us/magazine/2007.09.cableguy.aspx” rel=“nofollow noreferer” The Cable Guy

另见https://forums.codeguru.com/showthread.php?487139-Socket- binding-with-routing-table

On Windows, a call to bind() affects card selection only incoming traffic, not outgoing traffic. Thus, on a client running in a multi-homed system (i.e., more than one interface card), it s the network stack that selects the card to use, and it makes its selection based solely on the destination IP, which in turn is based on the routing table. A call to bind() will not affect the choice of the card in any way.

It s got something to do with something called a "Weak End System" ("Weak E/S") model. Vista changed to a strong E/S model, so the issue might not arise under Vista. But all prior versions of Windows used the weak E/S model.

With a weak E/S model, it s the routing table that decides which card is used for outgoing traffic in a multihomed system.

See if these threads offer some insight:

"Local socket binding on multihomed host in Windows XP does not work" at http://www.codeguru.com/forum/showthread.php?t=452337

"How to connect a port to a specified Networkcard?" at http://www.codeguru.com/forum/showthread.php?t=451117. This thread mentions the CreateIpForwardEntry() function, which (I think) can be used to create an entry in the routing table so that all outgoing IP traffic with a specified server is routed via a specified adapter.

"Working with 2 Ethernet cards" at http://www.codeguru.com/forum/showthread.php?t=448863

"Strange bind behavior on multihomed system" at http://www.codeguru.com/forum/showthread.php?t=452368

希望帮助!

我不敢肯定,为什么你说约束不可靠地工作。 赠款 我没有做详尽的测试,但以下解决办法对我来说是可行的(Win10, 视觉演播室,2019年)。 我需要通过某个特定的通信通信公司发出广播信息,因为计算机上可能会有多个通信通信公司。 在下表中,我希望广播信息能够与IP公司联系。

概述:

• create a socket
• create a sockaddr_in address with the IP address of the NIC you want to send FROM
• bind the socket to that FROM sockaddr_in
• create another sockaddr_in with the IP of your broadcast address (255.255.255.255)
• do a sendto, passing the socket created is step 1, and the sockaddr of the broadcast address.

............

static WSADATA     wsaData;

static int ServoSendPort = 8888;
static char ServoSendNetwork[] = "192.168.202.106";
static char ServoSendBroadcast[] = "192.168.255.255";

............ ...... < snip >

if ( WSAStartup(MAKEWORD(2,2), &wsaData) != NO_ERROR )
      return false;


// Make a UDP socket
SOCKET ServoSendSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
int iOptVal = TRUE;
int iOptLen = sizeof(int);
int RetVal = setsockopt(ServoSendSocket, SOL_SOCKET, SO_BROADCAST, (char*)&iOptVal, iOptLen);
              
// Bind it to a particular interface
sockaddr_in ServoBindAddr={0};
ServoBindAddr.sin_family = AF_INET;
ServoBindAddr.sin_addr.s_addr = inet_addr( ServoSendNetwork ); // target NIC
ServoBindAddr.sin_port = htons( ServoSendPort );
int bindRetVal = bind( ServoSendSocket, (sockaddr*) &ServoBindAddr, sizeof(ServoBindAddr) );
if (bindRetVal == SOCKET_ERROR )
{
    int ErrorCode = WSAGetLastError();
    CString errMsg;
    errMsg.Format (  _T("rats!  bind() didn t work!  Error code %d
"), ErrorCode );
    OutputDebugString( errMsg );
}


// now create the address to send to......
sockaddr_in ServoSendAddr={0};
ServoSendAddr.sin_family = AF_INET;
ServoSendAddr.sin_addr.s_addr = inet_addr( ServoSendBroadcast ); // 
ServoSendAddr.sin_port = htons( ServoSendPort );

......

#define NUM_BYTES_SERVO_SEND 20
unsigned char sendBuf[NUM_BYTES_SERVO_SEND];
int BufLen = NUM_BYTES_SERVO_SEND;

ServoSocketStatus = sendto(ServoSendSocket, (char*)sendBuf, BufLen, 0, (SOCKADDR *) &ServoSendAddr, sizeof(ServoSendAddr));
if(ServoSocketStatus == SOCKET_ERROR)
{
    ServoUdpSendBytes = WSAGetLastError();
    CString message;
    message.Format(_T("Error transmitting UDP message to Servo Controller: %d."), ServoSocketStatus);
    OutputDebugString(message);
    return false;
 }