[Kea-users] dhcp6 address assignment

Wed Oct 19 21:19:45 UTC 2022

I'm guessing you might need to use the flex_id hook library and define a
flex-id to make that work?  Though I don't really know as I have not looked
into using the flex_id hook library myself.

--Dan

On Wed, Oct 19, 2022 at 4:09 PM Marek Greško via Kea-users <
kea-users at lists.isc.org> wrote:

> Hello,
>
> I have one more question on that topic. I have one client having both
> ethernet and wifi interface in the same vlan/subnet. I want to assign ipv6
> address to both of them. Is it possible to differentiate by both duid and
> iaid?
>
> Thanks
>
> Marek
>
>
>
>
>
> Sent with Proton Mail secure email.
>
> ------- Original Message -------
> On Wednesday, October 19th, 2022 at 19:12, perl-list <
> perl-list at network1.net> wrote:
>
>
> >
> > ----- Original Message -----
> >
> > > From: "Marek Greško via Kea-users" kea-users at lists.isc.org
> > > To: "Dan Oachs" doachs at gac.edu
> > > Cc: "kea-users" kea-users at lists.isc.org
> > > Sent: Wednesday, October 19, 2022 12:59:56 PM
> > > Subject: Re: [Kea-users] dhcp6 address assignment
> >
> > > Hello,
> >
> > > I run into another problems with this. To simplify the migration I use
> global
> > > reservations. I have two definitions for that machine. One for
> ethernet adapter
> > > and one for wifi adapter. Unfortunately the DUID is the same with both
> > > interfaces so the kea-dhcp6 cannot start with that configuration. ISC
> DHCPD6
> > > hed no problem with that and everything was working correctly. It was
> because I
> > > was able to define both mac address and duid. Since I defined
> different value
> > > for mac for wifi there was no conflict.
> >
> > > Probably the only one solution for this is to drop global reservations
> and
> > > switch to per subnet reservations?
> >
> >
> > It would seem it is best to not use global reservations in your scenario:
> >
> > "This feature can be used to assign certain parameters, such as hostname
> or other dedicated, host-specific options. It can also be used to assign
> addresses or prefixes. However, global reservations that assign either of
> these bypass the whole topology determination provided by the DHCP logic
> implemented in Kea. It is very easy to misuse this feature and get a
> configuration that is inconsistent. To give a specific example, imagine a
> global reservation for the address 2001:db8:1111::1 and two subnets
> 2001:db8:1111::/48 and 2001:db8:ffff::/48. If global reservations are used
> in both subnets and a device matching global host reservations visits part
> of the network that is covered by 2001:db8:ffff::/48, it will get the IP
> address 2001:db8:ffff::1, which is outside of the prefix announced by its
> local router using router advertisements. Such a configuration is unusable
> or, at the very least, riddled with issues, such as downlink traffic not
> reaching the device."
> >
> >
> https://kea.readthedocs.io/en/kea-2.2.0/arm/dhcp6-srv.html?highlight=global
> reservation#global-reservations-in-dhcpv6
> >
> > > Thanks
> >
> > > Marek
> >
> > > ------- Original Message -------
> > > On Tuesday, October 18th, 2022 at 20:48, Dan Oachs doachs at gac.edu
> wrote:
> >
> > > > Have you looked at using multiple reservations for the same IP?
> Would that solve
> > > > any of your issues?
> >
> > > > [
> > > >
> https://kea.readthedocs.io/en/latest/arm/dhcp6-srv.html?highlight=unique#multiple-reservations-for-the-same-ip
> > > > |
> > > >
> https://kea.readthedocs.io/en/latest/arm/dhcp6-srv.html?highlight=unique#multiple-reservations-for-the-same-ip
> > > > ]
> >
> > > > --Dan
> >
> > > > On Tue, Oct 18, 2022 at 1:15 PM Marek Greško via Kea-users < [
> > > > mailto:kea-users at lists.isc.org | kea-users at lists.isc.org ] > wrote:
> >
> > > > > Hello,
> >
> > > > > I am in a phase of migration ISC DHCPD into kea and I am suffering
> several
> > > > > problems in ipv6 address assignment.
> >
> > > > > 1. I used to assign same ipv6 address for the same machine which
> was dial boot
> > > > > linux/windows. It was possible by assigning same ipv6 address to
> both DUIDs
> > > > > before. But in kea this is not allowed. I found out there is a
> possibility to
> > > > > assign ipv6 address by MAC address which was not possible in ISC
> DHCPD. I was
> > > > > very happy with that finding but fallen into second problem.
> > > > > 2. The windows machine got 2 interfaces ethernet and wifi. I
> configured kea to
> > > > > assign one ipv6 address to the ethernet adapter and another one to
> the wifi
> > > > > adapter. But after investigating logs kea was receiving dhcp6
> request over wifi
> > > > > using the ethernet adapter mac address. How is this possible? Is
> it possible
> > > > > the MAC address in DHCP does not match L2 MAC address? I did not
> sniff the
> > > > > request, yet. I decided to switch back to DUID assignment since
> this problem is
> > > > > worse than the previous.
> > > > > 3. Maybe it would be possible to overcome the above problems if
> kea is able to
> > > > > match both DUID and MAC address, but it is not allowed in kea. I
> am ought to
> > > > > select one option only. Why?
> >
> > > > > Thanks
> >
> > > > > Marek
> >
> > > > > Thanks
> >
> > > > > Marek
> >
> > > > > --
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