Thanks for the answer. I get your points and as you said, it seems safe to do it that way.
In case I want to force it through faster I can just delete the lease from the mysql as I did this time. I turned of laptop1 and it will not be used anymore so I should not be in risk of duplicate addresses. Br, Thomas On 01/06/16 21:24, "[email protected] on behalf of Tomek Mrugalski" <[email protected] on behalf of [email protected]> wrote: >On 01.06.2016 20:57, Thomas Andersen wrote: >> When assigning IP for a client, will dhcp lease always overrule host >> reservation? >It's complicated. In general, adding reservations for an address that is >used by someone else it a bad idea. Kea will sort that out, but it needs >some time for that (up to 2x renew-timer). > >If you added reservation for an address that is currently leased by >someone else, Kea will sort that out eventually. Existing user of the >address will not be able to renew it. laptop2 will get a >different address until the reserved address is in use by laptop1. > >This is explained in >http://git.kea.isc.org/~tester/kea/guide/kea-guide.html#reservation4-conflict. > >> My scenario is as follows: >> >> My laptop (laptop1) had a host reservation for a specific IP. >> >> I then get a new laptop (laptop2) and therefor change my host >> reservation to match the mac address for laptop2. >> >> For some reason I don’t get the intended IP assigned for laptop2. I >> found out that there was an active lease for that IP by laptop1 who >> had it assigned by host reservation prior. >> >> Is this working as intended? >Yes. > >> I expected, that because of the change in the host reservation, KEA >> would ignore the current leases and assign the IP to laptop2 despite >> of the lease for laptop1. >That wouldn't work. Just because you changed reservation, the laptop1 >will not magically stop using the address. laptop1 still thinks he's >entitled to use the address he got for its lease lifetime. Had Kea >assigned it to laptop2 as you suggested, laptop2 would discover >duplicate addresses, would report to Kea that the address is declined >and the reservation wouldn't work anyway. > >So what Kea will do: >1. try to assign reserved address to laptop2, but discover it's used by >laptop1. will temporarily assign a different address to laptop2. >2. when laptop1 tries to renew, it is NAKed. >3. The laptop1 will restart and get a different address. At this point >the address that was "occupied" by laptop1 becomes free. >4. Once laptop2 renews, it is also NAKed. >5. laptop2 restarts. Kea now sees that it has a reservation and that the >address is free, so assigns it to laptop2. > >This is not the fastest recovery procedure, but the safest one. It's >also fully autonomous, so does not require any manual intervention. >Personally I think about this as Kea cleaning up the mess sysadmin did :) > >Hope that helps, >Tomek >_______________________________________________ >Kea-users mailing list >[email protected] >https://lists.isc.org/mailman/listinfo/kea-users _______________________________________________ Kea-users mailing list [email protected] https://lists.isc.org/mailman/listinfo/kea-users
