There are also issues with end user rollouts. For example, comcast uses prefix delegation to give you are &#x2F;60 which your router (pfsense in my case) then uses for the internet network (it carves out a &#x2F;64). However, this prefix changes! As it is not a statically assigned prefix, my internal devices renumber whenever it changes, it would make it a huge pain to get a consistent mapping for my internal devices (media server, printer, etc) were I to go ipv6 only.<p>I thought about using an additional ULA subnet (ipv6 supports multiple subnets), but apparently many vendors do not yet support RFC 6724, or support it poorly with regard to ULA addresses. As such, I get mixed results with devices trying to use the ULA address for internet egress.<p>NAT66 (npt) is another possibility, and some people end up having to use this when they have more than one ISP (multi-wan balancing) anyway, but I haven&#x27;t found a good way to update the nat target when the prefix changes yet (might try moving to openbsd and try ifstated calling a script to a pf table or something).