[Kea-users] How to get kea to reassign same IP after an explicit release (client reboot) if it has not been reused

[Blažej Krajňák]

Hi Nathan,

I experienced the same strange behaviour. For me, the only solution
was to prohibit "release" packets at all. In database I inserted:

table: dhcp4_client_class
{"id":"3","name":"DROP","test":"pkt4.msgtype==7","next_server":null,"server_hostname":null,"boot_file_name":null,"only_if_required":"0","valid_lifetime":null,"min_valid_lifetime":null,"max_valid_lifetime":null,"depend_on_known_directly":"0","follow_class_name":null,"modification_ts":"2022-05-17
20:18:42","user_context":null}

table: dhcp6_client_class
{"id":"2","name":"DROP","test":"pkt6.msgtype==8","only_if_required":"0","valid_lifetime":null,"min_valid_lifetime":null,"max_valid_lifetime":null,"depend_on_known_directly":"0","follow_class_name":null,"modification_ts":"2022-05-17
20:16:00","preferred_lifetime":null,"min_preferred_lifetime":null,"max_preferred_lifetime":null,"user_context":null}


Blažej

so 8. 10. 2022 o 5:45 Nathan Neulinger <nneul at neulinger.org> napísal(a):
>
> From reading docs, it sure seems like these settings should result in the desired 'affinity' behavior, but it seems like maybe that is only working when it's an expiration, and not a 'release'?
>
>
>     "expired-leases-processing": {
>       "flush-reclaimed-timer-wait-time": 25,
>       "hold-reclaimed-time": 3600,
>       "max-reclaim-leases": 100,
>       "max-reclaim-time": 250,
>       "reclaim-timer-wait-time": 10,
>       "unwarned-reclaim-cycles": 5
>     },
>
>
> ________________________________
> From: Nathan Neulinger [mailto:nneul at neulinger.org]
> Sent: Friday, October 7, 2022 at 10:41 PM
> To: Kea-users at lists.isc.org <Kea-users at lists.isc.org>
> Subject: How to get kea to reassign same IP after an explicit release (client reboot) if it has not been reused
>
> Scenario:
>
>     Lightly used subnet, reasonably sized pool of addresses, served with an HA pair of Kea v2.2
>     Client issues a RELEASE as part of reboot process
>     Testing with v4 only at the moment
>
>
> The client appears get a new IP from the pool every time it reboots. It does this even when no other leases have been granted to or even requested by other devices in the mean time.
>
> While this is certainly "valid" behavior - a client can't _expect_ to get the same IP, especially if network is busy/small pool/etc. -- it's not particularly user friendly. It's also not at all what users are used to on a network that was previously using an ISC DHCPd pair.
>
>
> Is there any way to get Kea to hand out the same IP for a recently known client identifier if it has not already been given to another client? i.e. prioritize assignment of LRU priority on addresses in the pool unless it was the last client to be given a particular lease?
>
>
> Ideal would be if the above could be time limited. Something like a "hold time" on a release - where it stays 'assigned but claimable if necessary' to a given client for some defined number of minutes after it is released.
>
>
> Reservations are not what I'm looking for, we already have those, this is specifically in regards to 'purely dynamic pool' handling.
>
> -- Nathan
>
> ------------------------------------------------------------
> Nathan Neulinger                       nneul at neulinger.org
> Neulinger Consulting                   (573) 612-1412
>
> --
> ------------------------------------------------------------
> Nathan Neulinger                       nneul at neulinger.org
> Neulinger Consulting                   (573) 612-1412
>
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