MCLT and DHCP Failover

Matt Causey matt.causey at
Mon Nov 16 22:34:34 UTC 2009

On Mon, Nov 16, 2009 at 1:19 PM, Matt Causey <matt.causey at> wrote:
> I have a question about mclt and failover.  I've been through the man
> page and cant seem to find the answer....
> We have  very short MCLT on our failover pair.  We do this because we
> would like to see clients start getting leases ASAP, and we are less
> concerned about the leases integrity.
> We had a failover event, where a box was in partner-down for a long
> time, and handed out our 300 second lease time to a large number of
> clients.  As expected, we have about 1000 clients now with very short
> lease times.
> Both dhcp servers are healthy now, and communicating.  And, we're
> seeing lots of DHCPREQUEST/DHCPACK messages for these leases,
> obviously very short.
> So, the there anything I can do to cause the clients to
> start picking up the configured lease time again?

Hrm..nevermind.  After reviewing the source, it looks as though the
leases should get updated to the correct time after communications are
established again.    Not sure what was happening on my server, but
bouncing dhcpd on the secondary caused both servers to rip through all
the leases, updating them to their configured 12 hour time....



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