Enabling 002 Microsoft Release DHCP Lease On Shutdown Option

JC34209324 51 Reputation points
2021-10-07T23:37:21.7+00:00

Hello, is there a way to validate that the Microsoft Advanced Option 002 Release DHCP Lease On Shutdown Option is working when a workstation is rebooted or shut down?

I've enabled the option already and it has a value of "0x1". Is this correct or does the value need to be "0x00000001" as specified in the MS doc below? I confirmed the option was set in Server Options and is also present on all of the subnets' Scope Options. I've tested by rebooting a workstation (twice) that obtained its lease from the DHCP Server. I noticed that it kept the same IP Address after being rebooted, but the lease timestamp updated after each reboot. During this process, how do I know the workstation sent the DHCPRELEASE message?

I used this doc for reference - https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-dhcpe/4cde5ceb-4fc1-4f9a-82e9-13f6b38d930c

Thank you in advance for your input.

Windows Server
Windows Server
A family of Microsoft server operating systems that support enterprise-level management, data storage, applications, and communications.
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Windows DHCP
Windows DHCP
Windows: A family of Microsoft operating systems that run across personal computers, tablets, laptops, phones, internet of things devices, self-contained mixed reality headsets, large collaboration screens, and other devices.DHCP: Dynamic Host Configuration Protocol (DHCP). A communications protocol that lets network administrators manage centrally and automate the assignment of Internet Protocol (IP) addresses in an organization's network.
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  1. Gary Reynolds 9,391 Reputation points
    2021-10-26T20:45:47.92+00:00

    Hi @JC34209324

    The fact that the workstation has the same IP after a reboot doesn't necessarily mean that the IP address is not being released as the server could be issuing the same IP address.

    The easiest option to confirm that the workstation are sending the release is to enable the auditing on the DHCP server. This should contain the details of the requests that are being received by the server. The other option is to do a network capture of the workstation startup and shutdown process and monitor the DHCP traffic that is sent by the workstation. You will need to do this with network hub or a port mirror to to capture the traffic, or do the capture on the DHCP server, as most of the DHCP traffic is unicast.

    Gary.