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DHCP Problems - (Changed to lesser scope and expired leases arent renewing..)

Hi all,

So yesterday I changed my DHCP scope from 192.168.1.109-.199 to 192.168.1.150-.199
I assumed that when a lease expired with one of the lesser addresses it would renew with one of the higher up addresses. (Have less than 50 DHCP clients).

However, I made the change yesterday....and this morning alot of these machines would not renew their IP address! I had to assign static addresses....

What am I missing here??

(This is on a Windows 2003 domain, with a Win2008 server as the DHCP server)

Thanks!!!
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Zaheer Iqbal
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Your clients will not change IP's just because your scope has changed, they will keep them until the lease expires.

You need to release then renew the IP's from your clients to get them using the higher scope.

How the dhcp lease period works:
http://technet.microsoft.com/en-us/library/cc958908.aspx
http://technet.microsoft.com/en-us/library/cc780760(WS.10).aspx
http://technet.microsoft.com/en-us/library/cc958892.aspx
I believe machines will hold the old leases until they are powered off. I changed our DHCP  pool range from 10.0.100.x to 10.0.101.x - several weeks ago and there are machines still holding the old IP address lease.

Just because the DHCP pool range changes doesn't mean the usable IP range changes. Windows tries to retain it's last IP address.

I would manually delete leases from the server and force them to renew their DHCP leases to regain connectivity.
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Duhh!! ;)