Hello, In linux kernel source etheernet header is defined as structure as struct ethhdr { unsigned char h_dest[ETH_ALEN]; /* destination eth addr */ unsigned char h_source[ETH_ALEN]; /* source ether addr */ unsigned short h_proto; /* packet type ID field */ } __attribute__((packed)); I want to know what __attribute__((packed)) meance? It is not looking as a structure object then what is thati? regards, cranium -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/