IPv6地址是否可以在IPv4模式下工作？

Answer 1

每个接口都将使用mac地址导出一个链路本地ipv6地址。这个地址对于本地网络内的通信是足够的。关于socket的创建，您需要指定family(AF_INET和AF_INET6)，并初始化和绑定它。

IPv4:

     struct sockaddr_in serv_addr, cli_addr;
     sockfd = socket(AF_INET, SOCK_STREAM, 0);
     serv_addr.sin_family = AF_INET;
     serv_addr.sin_addr.s_addr = INADDR_ANY;
     serv_addr.sin_port = htons(portno);

     if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0)

IPv6:

     struct sockaddr_in6 serv_addr, cli_addr;
     sockfd = socket(AF_INET6, SOCK_STREAM, 0);
     serv_addr.sin6_family = AF_INET6;
     serv_addr.sin6_addr = in6addr_any;
     serv_addr.sin6_port = htons(portno);

     if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0)