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dhcp oddity

I have a task assigned to event id 1020 (windows 2008 r2) to send an email when a dhcp scope hits 80% usage. It had been working fine before when usage was high, but now it is showing that a particular scope is over 80% used when it isn't. When I look at the scope statistics, it shows there are 41 (82%) addresses in use with only 9 available. However, when I refresh the lease list, there are only 17 addresses being used, not 41. How is this possible?

Mal Osborne

Tried to "Reconcile all scopes"? (Right click "IPv4"). Sometimes the database becomes inconsistent, with what is in the registry and what is in the database differing.

Seth Simmons

ASKER

it says it is consistent
refreshed and has the same 17 in the list; statistics show 39 used

Jeremy Weisinger

Do you use IP conflict detection? If IP conflicts are detected it will remove them from the pool. Check the event log for
ID 1005. https://technet.microsoft.com/en-us/library/cc726935(v=ws.10).aspx

If you have a bunch of those it might account for the discrepancy.

Seth Simmons

ASKER

this pool is used for a small vdi deployment and the lease is short; the vlan is not used for anything else
if there was a conflict, it would appear in the console as BAD_ADDRESS

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Aard Vark

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Seth Simmons

ASKER

the output from netsh is accurate matching the statistics so something happened overnight fixing itself
will have to wait until this happens again; might be within a week since it happened last week

Seth Simmons

ASKER

happened again; netsh showed leases expired in the last couple hours but not made available yet for reuse. i increased the pool to keep under 80% and mitigate warning emails