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Lease Duration Not Being Honored RRS feed

  • Question

  • We recently created two 2012 R2 DHCP servers to our environment to utilize the load balancing feature (50/50). Recently, we discovered that the leases being issued from the secondary server are applying a 4 hour expiration and not the set parameter of 8 days.  Here is what I did.  I deleted the failover setup.  Released my IP address and renewed (got a new IP address).  The 8 days was applied correctly.  I recreated the failover and the lease expiration on the secondary server displayed correctly.  I again, released and renewed and the expiration date changed to 4 hours.  I refreshed the view on the secondary server and it too, displayed the 4 hour lease time.  We have applied the latest updates and KB2919355 (DHCP related fix) is applied.  It looks as though the set parameter is not being applied and the aging/scavenge time frame is.

    Is anyone seeing this behavior and if so, have a solution?

    Thank you for any assistance in this matter!

    K. Richie

    Monday, May 4, 2015 4:16 PM

Answers

  • I contacted MS Support and it was explained that this is by design.

    First, I was incorrect in my changed lease time . . . it was not 4 hours, it was an hour.  This is applied by the MCLT (maximum client lead time) from the failover server.  Here is the link, which describes the behavior:

    Google  dn338973   DHCP Failover Examples

    The 1 hour lease time was applied because we performed an ipconfig /release & renew.  Had we then performed an ipconfig /renew once again, the correct lease period would have been applied to the client.  If we had waited about 30 minutes (50% of the lease time or more), it would have updated and reflected the lease time configured in the scope automagically.

    I hope this post helps someone else out!

    K. Richie

    • Marked as answer by krichie Tuesday, May 5, 2015 7:19 PM
    Tuesday, May 5, 2015 7:18 PM