DHCP Lease Expired -- Windows 2003

My DHCP server still shows the attached leases, but they are already expired (past the 10hr period)

In the past I looked at this I was thinking it did NOT show already expired leases.

I rebooted the server, RESTARTED the DHCP service, etc,
but the expired leases are still displaying instead of going away.

 1. Do expired leases stay until someone else uses the IP address ?
 2. Is my DHCP server maybe failing to DROP these expired leases now ?
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SandeepSr System AdministratorCommented:
On a Windows Server 2003 DHCP server, when an DHCP lease expires, the lease is marked for deletion in the DHCP database. It isn't immediately deleted from the database however. Instead, DHCP clients are granted a 4 hour reprieve just in case they still need to use the address so they can renew it. After this grace period elapses, the expired lease can be reused by another client requesting an IP address. Once per hour the DHCP server runs a cleanup cycle which reclaims unused leases. If you have lots of DHCP clients issuing requests on your network and there are no leases available, the DHCP cleanup cycle runs immediately, reclaiming leases marked for deletion so new leases can be issued to clients requesting them. You can modify the cleanup cycle to run more frequently (if you are short of available leases) or less frequently (if you have a large pool of available leases) by modifying the registry key HKLM\System\CurrentControlSet\Services\DHCPServer\Parameters\LeaseExtension
finance_teacherAuthor Commented:
The below will happen if I don't
have all my IPs used, correct ?
  ** 6:02 am = lease expired
  ** 10:02 am = server is READY to release IP if needed NOW
  ** 11:00 am = hourly cleanup releases IP if not already done (could be changed if desired)
SandeepSr System AdministratorCommented:
Yes...Try modifying the LeaseExtension time to release the expired IP
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SandeepSr System AdministratorCommented:
Also can you advise what value you have @DatabaseCleanupInterval in same path i.e. HKLM\System\CurrentControlSet\Services\DHCPServer\Parameters\

This value is described in minutes, and if this is more than 4 hour or so, you can reduce the same by using below command

netsh dhcp set databasecleanupinterval <Minutes>


Just modify the minutes what you want to put, you can try with making it as 60. So every one hour data base clean up will be done.
finance_teacherAuthor Commented:
My DHCP server has HKLocalMachine\System\CurrentControlSet\Services\DHCPServer\Parameters\, but no LeaseExtension under that.  It does have DatabaseCleanupInterval = 60 (decimal) --> 3c (hexadecimal)

I assume this is OK and LeaseExtension was just never created in Windows 2003 ?
SandeepSr System AdministratorCommented:

Try adding as below

DHCP Grace Period = Amount of time AFTER DHCP lease expires before it is subject to DHCP clean up (default = 4 hours!)
Can be set by adding HKLM\System\CurrentControlSet\Services\DHCPServer\ Parameters\LeaseExtension DWORD reg key (in minutes)
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