setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl));
setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL, &ittl, sizeof(ittl));
setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl));
setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL, &ittl, sizeof(ittl));