Shortening lease on one subnetL: need reduce MCLT for all?

Nick Urbanik nick.urbanik at
Mon Dec 7 05:51:41 UTC 2015

Dear Folks,

On an ISC DHCP server failover pair, version 4.2.5, I need to shorten
the maximum DHCP lease time for one subnet from 2 hours to 20 minutes
temporarily to allow the IP address ranges to be expanded.  This is
together with a Cisco ASR9k that I am told is working as a caching
relay for the DHCP server pair.

Now it seems reasonable to reduce the MCLT to ten minutes during the
work.  Is that correct?  From my understanding, there will be rather
counterproductive behaviour if the MCLT is left longer than the
maximum lease: is that not the case?
Nick Urbanik 808-71011 nick.urbanik at
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I disclaim, therefore I am.

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