Is it possible to have DHCPv6 assign both a local and a global address

ChrisJenk

My home network is dual stack. All devices get a local IPv6 address (fd00::/64) assigned either via manual assignment (servers) or DHCPv6.

Is it possible to also have DHCPv6 assign global addresses to the same set of clients (based on my global IPv6 /64 prefix) on the same network? If so how to configure it?

If it is possible, is it also possible to limit which clients get assigned global addresses?

Thanks.

Bob.Dig

@chrisjenk Use DHCPv6 with Track Interface for the GUA and Subnets on RA for ULA.

Change Router Mode to something usefull like assisted.

JKnott

@bob-dig

Of course, there's also SLAAC, instead of DHCPv6. DHCPv6 does not work with Android devices.

ChrisJenk

@bob-dig Thanks, but ideally I want to control the address that gets assigned, both local and global. Currently I can do that using the DUID for DHCPv6 for local addresses but if I switch to RA then I no longer have that control :-(

ChrisJenk

@chrisjenk So I found the best solution for me based on these suggestions (thanks!).

I have the DHCPv6 server set to hand out ULAs and have also set up some static mappings for key mobile devices.

fd00::xxxxxxxxxxx

I have the RA set to Assisted and I specify only the GUA address range there

2001:aaaa:bbbb:cccc::xxxxxxxxxxxxx

What I see now is that Apple devices (which do support DHCPv6) get 5 addresses:

fd00::<reservation> via DHCPv6
fd00::xxxxxxxxxxxx via SLAAC
fdbd:<psudo random> - some private address that Apple insists on generating/assigning but which is otherwise useless
2001:aaaa:bbbb:cccc::qqqqqqqqqqqqq - regular global address via SLAAC
2001:aaaa:bbbb:cccc::yyyyyyyyyyyyyyy - temporary global address via SLAAC

This is fine for me since the device has a well known private address (which I want/need) plus it has full IPv6 Internet access etc.

Other devices that do not support DHCPv6 get the SLAAC addresses so they also work as expected (but without a well known address, which is fine as there are very few such devices in my network).

Problem solved!

Bob.Dig

@chrisjenk said in Is it possible to have DHCPv6 assign both a local and a global address:

@chrisjenk So I found the best solution for me based on these suggestions (thanks!).
Problem solved!

Until your GUA-Prefix changes, then you have to manually reassign it. That is why I would do it the other way around, GUA via Track Interface (and DHCPv6) and ULA via RA.

But if your prefix is not dynamic then this doesn't apply to you.

ChrisJenk

@bob-dig Yes, what you say is true. Luckily my prefix(es) are not dynamic and I'd need to do quite a few changes to flip to what you suggest. I'll probably think about that as a longer-term project but for now this solution works for my specific use case.