Hot standby DHCP server not taking over scope.

pkfwallast
pkfwallast used Ask the Experts™
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I have setup a failover DHCP server configuration in Hot standby mode between two Windows 2012 R2 servers in the same subnet. The Max Client Lead Time is 5 minutes and the State Switchover Interval is 15 minutes. The addresses reserved for standby is 0% because we don't have enough addresses.

When I stop de DHCP server on the primary server after 15 minutes the hot standby server switches the scope over to partner down and 5 minutes later it's serving out IP-addresses. Only now comes the problem / fun part. The stand-by server is leasing out correct ip-addresses from the scope, but it does it with the 5 minutes lease time as configured in the MCLT. He does this for the entire time the Primary server is down. So every 5 minutes it leases the same ip-adres to the client for an other 5 minutes. over and over again.

Is this normal behavior? I thought that after 15 minutes of switchover interval plus the 5 minutes of MCLT it takes over the complete scope and acts like it's the primary server.
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Commented:
Maximum client lead time defines how much time extension a partner server can provide to a client, based on time known by partner server. You have set that to 5 minutes, so the Standby DHCP server can only extend the DHCP Lease for an additional 5 minutes.

State switchover interval controls how long standby server waits after losing communication with primary server before assuming active state and servicing DHCP clients.

Change your Max Client lead time to whatever you want the Standby DHCP server to be. It will take over as Primary DHCP but will still follow all of the directives you have set it up with.
I thought the standby server would take over the scope and would act like the primary with the same lease times etc, but it's logical that it wouldn't act the same because it's the standby server and it expect the primary server would be temporarily down. That's why it only extends new or existing leases with the MCLT time.

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