udhcpc6 only support DUID-LL in the client ID option for dhcp request. I would like to have a command line option to support the other client ID types per rfc3315 section 9(DHCP Unique Identifier (DUID)). Example. -C OPT:VAL Override client id 1:Time[:MAC] - (DUID-LLT) = Time since 2000-01-01 in seconds + mac address(optional) 2:Ent-num:Id - (DUID-EN) = enterprise-number(integer) + identifier (Ex. 23425:0100BEEFC0FFEE) 3[:MAC] - (DUID-LL) = MAC address (optional) default 4:UUID - (DUID-UUID) = first 16 hex bytes 5:RAW - (RAW) = hex byte format