Primary / Secundary cluster with synced leases created using omapi

Shawn Routhier sar at
Sat Aug 6 21:20:53 UTC 2016

> On Aug 6, 2016, at 1:43 PM, S Carr <sjcarr at> wrote:
> On 6 August 2016 at 21:29, Matt . <yamakasi.014 at> wrote:
>> What you say happens, but when I reboot a machine with the secondary
>> dhcp server available only it doesn't get the same IP as it did before
>> failover....
>> You say I should see a refresh of all IP's/Mac as they were assigned
>> on the primary ? I need to check but I don't see that  think.
> Primary should be syncing the leases to the secondary (and vice-versa)
> so both peers have the same MAC to IP mapping for the client. Normally
> DHCPD doesn't purge/reuse IP addresses until it needs to, so as long
> as you have sufficient IP addresses in the subnet then the client
> should get the same IP it had previously.

It is true that the servers don’t purge leases in general.
But if the lease is allowed to expire it will go to either
free (on the primary) or backup (on the secondary).

If the server that owns that address is unavailable then
when the other server provides an address the client
won’t be able to get the original address.
> If it's not then either your client is changing it's MAC address or
> something else is causing DHCPD to reuse the lease once the client
> releases it on shutdown, so it's not available when it comes back
> online.

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