struct sockaddr_in {
short   sin_family; 
u_short sin_port;            /*Port number       */
struct  in_addr sin_addr;    /*Internet address  */
char    sin_zero[8];
};
----
struct sockaddr_in6 {
short   sin6_family;
u_short sin6_port;
u_long  sin6_flowinfo;
struct  in6_addr sin6_addr;
u_long  sin6_scope_id;
};
----