For my internal Network, i'd like to set up IPv6 with ULAs assigned with DHCPv6, a bit like with IPv4s RFC1918 private addresses:

  • I'm independent from the Prefix of my ISP for the internal networking

  • I can use DHCPv6 to assign adresses to clients/servers

  • I can set up DNS properly (dynamic updates of clients, interanl name resolution, reverse-zone)

especially the configuration of DNS and DHCPv6 are the points where i have to rely on the ULAs as far as i know, since i can't create stateful dhcp-configurations or DNS reverse-Zones based on a dynamically assigned prefix from my ISP

At the same time, i still want my clients to have a global addresses (with privacy extensions) which they should use for external communication.

My initial thought was to assign the ULAs with DHCPv6 from a server on the network (i have a DNS/DHCP-server already doing the same in the IPv4-World), and the global address with the RA of the router.

So, my questions:

  • afaik, clients should support this generally, but do the actually do this (request 1 adress with dhcpv6 AND another via neighbor discovery/router advertisement/SLAAC)
  • for clients which don't support this, how do i accomplish connectivity to either external and internal network? (Clients with ULA only or global adress only) I think of a NAT-mechanism like NPTv6 (NOT!!! NAT66)
  • is there any major flaw in this logic which i just can't see? Maybe i'm still thinking too much in IPv4, this was the 1st concept that came to mind for this problem.

another solution would be to scratch the assignment of global addresses to the clients at all and use only ULAs, DHCPv6 and NPTv6.

Best regards.

  • You can also get provider-independent global addressing from your RIR.
    – Ron Maupin
    Commented May 4, 2017 at 14:46

1 Answer 1


The basic idea is good. Using both global and ULA addresses in parallel works fine.

The only problem you might run into is that not all clients support DHCPv6 (notorious one is Android) so those clients will only get a global address through SLAAC, so its communication to ULA addresses will go through the router.

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