DHCP failover doesn't receive DHCP requests in secondary server

[Simon Hobson]

Anders Löwinger <anders at abundo.se> wrote:

> We have tried running with "split 255;" for a couple of hours (lease time 30 min) but saw no real difference on the load between the two dhcp servers....

Was that with existing leases ? If so then I think that's what you should see. Clients renewing an existing lease will initially send (by unicast) a request to the server that issued their lease - which will look in the leases database and find that the lease belongs to itself, and I would guess that this will bypass the split evaluation.
If you get clients to release their leases and then renew, I'd guess that you'll see the split value take effect.