[Kea-users] Lease allocation on option 82

Francis Dupont fdupont at isc.org
Thu May 2 11:48:37 UTC 2019


=?UTF-8?Q?Bj=C3=B8rn_Skovlund?= writes:
> I'm rather new to KEA, so I might be asking an obvious question.
> 
> We added the premium hooks, in the interest of the flex-id, however I'm
> coming up a bit short for our use-case.
> 
> We want to assign leases based on option 82, sub 2, which I've extracted
> with the flex-id and mapped to client-id with replace-client-id. However,
> it seems that this only works for host reservations and I was hoping to use
> it for lease assignment.

=> with replace-client-id it should work with leases too even the flex-id
feature was designed mainly for host reservations.

> Use case:
> We get endusers online with unknown option 82 and want to assign one, and
> only one, IP address to this option 82, sub 2. If the enduser comes online
> with a new MAC address, we want to offer them the same IP that they
> originally got.

=> if the synthesized client-id is the same it should be considered as
the same client (unless match-client-id was explicitly set to false).
But this does not enforce to get the same IP: you need a known lease for
the client and expired leases are reclaimed (so become unknown) after a
(settable) delay.

> It seems this would be possible with a host reservation on the client-id,
> but I'm trying to avoid having to copy the lease information into host
> reservations.

=> host reservations are of course the only way to really reserve an address.
But you can play with lifetime and expired-leases-processing timers to
make more likely a client to get the same IP address.

Regards

Francis Dupont <fdupont at isc.org>


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