System Administration Guide: IP Services

Protocol Details

With DHCPv4, the DHCP server supplies the subnet mask to be used with the assigned address. With DHCPv6, the subnet mask (also known as “prefix length”) is assigned by the Router Advertisements, and is not controlled by the DHCP server.

DHCPv4 carries a Hostname option that is used to set the system-wide node name. DHCPv6 has no such option.

To configure a Client ID for DHCPv6 you must specify a DUID, rather than allowing the system to choose one automatically. You can do this globally for the daemon, or on a per-interface basis. Use the following format to set the global DUID (note the initial dot):


To set a particular interface to use a given DUID (and make the system appear to be multiple independent clients to a DHCPv6 server):

hme0.v6.CLIENT ID=<DUID>

Each Identity Association (IA) holds one type of address. For example, an identity association for temporary addresses (IA_TA) holds temporary addresses, while an identity association for non-temporary addresses (IA_NA), carries assigned addresses that are permanent. The version of DHCPv6 described in this guide provides only IA_NA associations.

Oracle Solaris assigns exactly one IAID to each interface, on demand, and the IAID is stored in a file in the root file system so that it remains constant for the life of the machine.