[Kea-users] Kea 2.4.0 and duplicate host reservations not working as documented

[Kevin P. Fleming]

On Sun, Oct 22, 2023, at 10:17, Darren Ankney wrote:
> It then goes on to print details about the existing lease.  You could
> possibly use the flex-id hook to overcome this (in certain situations
> where there is something else to use as the identifier such as
> circuit-id).  Alternatively, you could use the API to delete the lease
> for 192.168.88.192 soon after granting so that it is free for your
> other interface.  However, this could lead to strangeness should the
> original interface try to renew (because the lease will no longer be
> found and renewal will fail).  If it's possible, it would be best to
> assign a separate address for each interface on the system.

Thanks, at least I understand why this is happening now.

I've tried other ways to address this on the client side (trying to use a stable DUID or CID to have Kea think it's the same client regardless of interface), but that doesn't seem to work out well either.

The primary problem I'm solving here is that this client makes a lot of outbound SSH connections to other machines on the network, and in order to speed these up SSH persistent control channels are used. If the client attempts to re-establish one of these connections after its IP address has changed, SSH will just hang for quite a long time. Clearly the SSH client could handle this better, but having a stable IP address is a more straightforward fix.

If there's no ticket open as a feature request for Kea to provide a method for the existing leases to be ignored when a new REQUEST comes in, I'll happily create one.