Client still hanging on to (now deleted) Microsoft Server 2008 DHCP reservation

budgetblinds
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So we have a typical run of the mill Microsoft Windows Server 2008 DHCP scope set up on our domain network. We have a small handful of clients, that are issued reserved DHCP IP addresses, that allow them "full internet" access. I need to now remove a client.

I deleted the computer/IP reservation in the DHCP Reservations area. Our lease times are only 1 day in length. It's been a few days, and the client keeps being able to renew or grab the same IP. I've even tried re-starting the DHCP Server services, but still no dice.

Am I just overlooking something really simple here ?

Thanks!
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So the client still on network and you dont want it to use this address anymore?
You need to reset the client pc settings -- give them a static ip or do a ipconfig /release, ipconfig /renew on client. The client still sees that address as its preferred address, and even though removed from the scope, will continue to use it until you have cleared it.
If you watch the offers and acks using something like wireshark it may show a few things.
when it renews I assume you'll see its simply being offered the same IP, If you look at the way leases work 12 hours in to the lease it will extend assuming that IP is free and the DHCP server responds. I have found a release/renew often produces the same IP which is annoying!

If you add that IP as a temporary exclusion then it will be offered another IP from the scope when it looks to renew on its own or you can do a manual release/renew. then you can delete the scope after the 24 hours or when it has the new IP. dirty way to do it but will solve your issue if its causing grief within the day.

Author

Commented:
Good idea of assigning a bogus client to the IP that was being used previously by this client. I was simply trying not to have to go to the client machine that is losing their "full internet" access and do ipconfig /release & /renew.

Thanks guys, I'll report back after seeing a solution work. Any other methods or ideas, feel free to leave them.

Thanks

Author

Commented:
Made a bogus reservation entry for the IP I needed back. Worked like a charm.

Thanks!

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