Hi All:
   I am confused by the bind useage.
   My OS is linux redhat 7.1 with kernel 2.2.
   When I make a program to received a broadcast message (255.255.255.255).
   If I bind the address with INADDR_ANY, I can receive the broadcast
message.
But if I bind with ipaddess with my netcard with the ip 192.168.0.33, then I
can
not receive any more.
   Below is the source code, please give me some advices.
   Thank you and best regards!

Leo

#include <stdio.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <sys/socket.h>

#define SERV_UDP_PORT 3233

char recvbuffer[1024];

int main()
{
    int  sockfd;
    struct sockaddr_in serv_addr, cli_addr;
    int localip, on;
    unsigned int socklen;
    /*
     * Open a UDP socket (an Internet datagram socket).
     */

    if ( (sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
    {
        printf("server: can't open datagram socket");
        return -1;
    }

    /*
     * Bind our local address so that the client can send to us.
     */

    localip = inet_addr("192.168.0.33");
    printf("local ip address %d\n", localip);
    bzero((char *) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family      = AF_INET;
#if 0
    serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
#else
    serv_addr.sin_addr.s_addr = localip;
#endif
    serv_addr.sin_port        = htons(SERV_UDP_PORT);
    printf("local ip port %d\n", serv_addr.sin_port);

    on = 1;
    if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof (on)) < 0)
    {
        printf("setsockopt of SO_REUSEADDR error");
    }

    if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0)
    {
        printf("server: can't bind local address");
    }

    socklen = sizeof(struct sockaddr_in);

    if (getsockname(sockfd, (struct sockaddr *) &cli_addr, &socklen) < 0)
    {
        printf("getsockname() error\n");
    }

    printf("bind address is [%ld] port is [%d]\n", cli_addr.sin_addr.s_addr,
cli_addr.sin_port);

    for (;;)
    {
        int n;
        socklen = sizeof(struct sockaddr_in);
        n = recvfrom(sockfd, recvbuffer, 1024, 0, (struct sockaddr
*)&cli_addr, &socklen);
        if (n < 0)
        {
            printf("recvfrom error\n");
            continue;
        }
        recvbuffer[n] = '\0';
        printf("received message: %s\n", recvbuffer);
    }

    return 0;
}