HI all, I am writing simple dhcpv6 client. I gone through the rfc of dhcp and ipv6 and understand basic. With the understanding i started to implement SOLICIT request option. I have created a packet with the below structure. struct udp_dhcp6_packet { struct ip6_hdr ip; struct udphdr udp; struct dhcp6_Message data; } PACKED; In the above structure i am able to assign the value for udp and data(i.e struct udphdr, struct dhcp6_Message). But i could not able to set the value for ip. Below is the structure of ip6_hdr. struct ip6_hdr { union { struct ip6_hdrctl { uint32_t ip6_un1_flow; /* 4 bits version, 8 bits TC, 20 bits flow-ID */ uint16_t ip6_un1_plen; /* payload length */ uint8_t ip6_un1_nxt; /* next header */ uint8_t ip6_un1_hlim; /* hop limit */ } ip6_un1; uint8_t ip6_un2_vfc; /* 4 bits version, top 4 bits tclass */ } ip6_ctlun; struct in6_addr ip6_src; /* source address */ struct in6_addr ip6_dst; /* destination address */ }; I want to set the ip6_dst value as ff02::1:2 and the ip6_src address as fe80::220:4aff:fea8:8e4a and remaining options. But i dont have any idea how to set these values. I googled many times and not able to get the idea to creat ipv6 header. Kindly help me to solve my problem? Note : I don't know whether this is right place to ask this question . If i am wrong , i am sorry. Thanks in advance , Prabhu