[ipv6hackers] Question on DHCPv6 address assignment

Marc Heuse mh at mh-sec.de
Sat Feb 1 09:57:59 CET 2014

when I looked at the DHCPv6 servers 4 years ago, most of them (that I
looked at) were handing out the addresses incrementally.
when I reported those as a problem, this was changed to random.
Currently I am not aware of a DHCPv6 server that hands out addresses
incrementally anymore, but you never know.

but what you see in the example config files (and that is what people
90% use) - something like ::1000-::2000 is used. thats 2048 addresses.
scan these for all documented examples (I found 5 or 6) and you scan all
of them pretty fast.

no clue on the renewing mechanism, my guess is they renew what they got
as this is the standard behavior in IPv4.


Marc Heuse

PGP: AF3D 1D4C D810 F0BB 977D  3807 C7EE D0A0 6BE9 F573

Am 31.01.2014 22:00, schrieb Fernando Gont:
> Folks,
> I'm wondering about the following two aspects of different DHCPv6
> implementations out there:
> 1) What's the pattern with which addresses are generated/assigned? Are
> they sequential (fc00::1, fc00::2, etc.)?  Random? Something else?
> 2) What about their stability? Is there any intent/mechanism for them to
> be as "stable" as possible? Or is it usual for hosts to get a new
> address for each lease?
> P.S.: I understand this is likely to vary from one implementation to
> another... so please describe which implementation/version you're
> referring to.
> Thanks!
> Best regards,

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