Maybe a host reservation is a solution?
From: Kea-users <[email protected]> On Behalf Of Johannes Midgren
Sent: Wednesday, 10 November 2021 15:47
To: [email protected]
Subject: [Kea-users] Lease affinity of released leases
TLDR: How do I make KEA offer the same IP to a host that is rebooted and that
releases its IP address while shutting down?
I have recently started to use KEA on my home network. I love the fact that I
can control its configuration through Ansible and all the possibilities the
REST API gives, so I'm very glad that I found the project!
One thing that I still have not been able to get the way I prefer it though, is
to have lease affinity in all cases. That is, I would like for a client to
always get the same IP address when it reconnects (as long as it's still
available of course). I have read the chapter about Lease Expiration (and
Affinity) in the manual and I'm not sure the case I'm looking for is covered.
The manual talks about expired leases, but I would like to have affinity also
in the case that the lease has been released rather than expired. Using a
packet sniffer I can see that clients tend to properly release the DHCP lease
when being rebooted and when it gets online again it does a DHCP Discover and
is offered a new IP address by the KEA DHCP4 server.
Does anyone know if KEA is supposed to (or rather can be made to) work the way
I intend it to or if lease affinity by design is only supposed to work for
expired, thus not released, leases? (Or maybe something is wrong with my setup
and this should actually work?)
The problem I have is that cached DNS entries make hosts unavailable for some
time after they are restarted - they are "sought for" by their old IP. I guess
I can mitigate the issue by setting a very low TTL in my DNS configuration, but
I would prefer to let KEA hold leases for a long time and reuse them instead.
Another way would of course be to make reservations for all hosts where this
matters, but that prevents the automation that I try to use KEA for.
I have been playing with the expired-leases-processing configuration for the
DHCP4 server, and I currently have this:
"expired-leases-processing": {
"flush-reclaimed-timer-wait-time": 300,
"hold-reclaimed-time": 604800,
"max-reclaim-leases": 100,
"max-reclaim-time": 250,
"reclaim-timer-wait-time": 180,
"unwarned-reclaim-cycles": 5
},
I'm running KEA 1.8 (installed from CloudSmith repos) on CentOS Stream 8. I use
the memfile lease-database, have DHCP-DDNS setup and I use the HA hook (with
one primary, one standby and one backup host).
_________________________________________________________________________________________________________________________
Ce message et ses pieces jointes peuvent contenir des informations
confidentielles ou privilegiees et ne doivent donc
pas etre diffuses, exploites ou copies sans autorisation. Si vous avez recu ce
message par erreur, veuillez le signaler
a l'expediteur et le detruire ainsi que les pieces jointes. Les messages
electroniques etant susceptibles d'alteration,
Orange decline toute responsabilite si ce message a ete altere, deforme ou
falsifie. Merci.
This message and its attachments may contain confidential or privileged
information that may be protected by law;
they should not be distributed, used or copied without authorisation.
If you have received this email in error, please notify the sender and delete
this message and its attachments.
As emails may be altered, Orange is not liable for messages that have been
modified, changed or falsified.
Thank you.
_______________________________________________
ISC funds the development of this software with paid support subscriptions.
Contact us at https://www.isc.org/contact/ for more information.
To unsubscribe visit https://lists.isc.org/mailman/listinfo/kea-users.
Kea-users mailing list
[email protected]
https://lists.isc.org/mailman/listinfo/kea-users
