On Sep 19, 2013, at 7:01 PM, Kevin Darcy <kcd@xxxxxxxxxxxx> wrote: > What would be the preferred way to provide a mixed list of IPv4 and IPv6 addresses, in a DHCPv6 option? IPv4-mapped addresses? The preferred way would be not to do that. I think there is a document floating around out there somewhere that uses IPv4-mapped addresses this way, but in general if you are configuring an IPv4 stack, you ought to be using DHCPv4. Otherwise DHCPv6 winds up being a transition technology in perpetuum. To be clear, you definitely should not expect a DHCPv6 client to do something meaningful with an arbitrary IPv4-mapped IPv6 address. It's anybody's guess where this would clog the plumbing, but it almost certainly wouldn't work.