Hi Aaron,

This is just a guess. Assuming you have something in (or have accepted
the defaults of) "max-unacked-clients" and "max-ack-delay" (see here:
https://kea.readthedocs.io/en/stable/arm/hooks.html#load-balancing-configuration)
then you'll need to make use of -y and -Y (see here:
https://kea.readthedocs.io/en/stable/man/perfdhcp.8.html) in perfdhcp
to simulate a failover event + actually have Kea failover.  Something
like:

perfdhcp -6 -e address-and-prefix -r 1 -R 100 -Y 5 -y 300 -p 300

would send dhcp6 queries with ia_na and ia_pd requests at the rate of
1 per second simulating a total of 100 clients.  five seconds into the
test it will start increasing the dhcp6 elapsed seconds option.  It
will do this for 300 seconds.  The -p causes the test to run for 300
seconds.  Shut down your primary Kea server sometime after starting
perfdhcp and failover should occur.

You should see log messages like this one:
https://kea.readthedocs.io/en/stable/kea-messages.html#ha-communication-interrupted-client6-unacked
until more clients than "max-unacked-clients" are encountered at which
point the standby or secondary server should start to answer the
clients.

Thank you,
Darren Ankney

On Tue, Dec 2, 2025 at 3:49 PM Aaron Gould <[email protected]> wrote:
>
> Hi KEA Users, my 2 server engineer coworkers and I (i'm the network guy)
> are trying to setup KEA HA Failover for the first time, in our lab.  We
> have lab endpoints and perfdhcp to test with.  We are generating
> hundreds of dhcpv6 ia_na and ia_pd requests, and the juniper dhcpv6
> relay router is logging the binding states just fine.  We try to
> failover the primary kea server, and see if the backup kea server will
> start replying to dhcpv6 requests, but the backup never seems to respond.
>
> I read some of a previous post from April 2016, but need a bit more
> guidance, lessons learned, and perhaps up-to-date 2025 info.
>
> I would appreciate any guidance any of you all could provide.
>
>
> --
> -Aaron
>
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