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我有在 RedHat Enterprise Linux5.5 中接收广播数据包的 ac 示例代码，以下是关键源：

struct ip_mreq {
    struct in_addr imr_multiaddr;    /* IP multicast address of group */
    struct in_addr imr_interface;    /* local IP address of interface */
} mreq; 

serv_addr.sin_addr.s_addr = inet_addr("225.0.100.100");
portno = 10000 ;
serv_addr.sin_port = htons(portno);
mreq.imr_multiaddr = serv_addr.sin_addr; 
mreq.imr_interface.s_addr = INADDR_ANY ;
//mreq.imr_interface.s_addr = inet_addr("192.168.165.212");
setsockopt(newsockfd, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mreq, sizeof(mreq));
setsockopt(newsockfd, SOL_SOCKET, SO_REUSEADDR, &set, sizeof(set));

路由表是：

[root@linux01 ~]# route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface

192.172.165.0 * 255.255.255.0 U 0 0 0 eth0

128.110.10.0 * 255.255.255.0 U 0 0 0 eth2

225.0.0.0 192.172.165.212 255.255.0.0 UG 0 0 0 eth0

169.254.0.0 * 255.255.0.0 U 0 0 0 eth0

默认 128.110.10.254 0.0.0.0 UG 0 0 0 eth2

我使用 tcpdump -i eth0 -nn 看是否成功加入广播组，

mreq.imr_interface.s_addr = INADDR_ANY ;
//mreq.imr_interface.s_addr = inet_addr("192.168.165.212");

将显示：

16:14:24.322672 IP 192.172.165.212 > 225.0.100.100：igmp v2 报告 225.0.100.100

mreq.imr_interface.s_addr = INADDR_ANY ;
//mreq.imr_interface.s_addr = inet_addr("192.168.165.212");

这不会有 igmp v2 报告消息！

我的问题是：为什么 INADDR_ANY 有效，但不是 inet_addr("192.168.165.212");

我错过了什么？

eth0 inet addr:192.172.165.212 Bcast:192.172.165.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1

eth2 inet addr:128.110.10.69 Bcast:128.110.10.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1

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