Hi, I try to send data to broadcast address with following code: struct sockaddr_in server; setuid(0); system("/sbin/ifconfig wlan0 down"); system("/sbin/ifconfig wlan0 address 10.0.0.1 up"); system("/sbin/iwconfig wlan0 mode Ad-Hoc essid masum"); sock = socket(AF_INET, SOCK_DGRAM, 0); setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, "wlan0", 6); int i=1; setsockopt(sock, SOL_SOCKET, SO_BROADCAST, &i, sizeof(int)); port = 6666; bzero(&server,sizeof(server)); server.sin_family = AF_INET; inet_aton("10.255.255.255",&server.sin_addr.s_addr); server.sin_port = htons(port); sendto(sock, "Hello from 770!", 16, 0, (struct sockaddr*)&server, sizeof(server)); close (sock); I have omitted error checking but no function call returns error code. Only signs of error are that there is no packet in receiving side, and when I check ifconfig there is one or two TX errors after I run the code. When I change the IP address to real address, sending works, and I can receive broadcast packets with the device. What's wrong? -Ari