Unable to add DHCP Scope: Scope parameters are incorrect

M Kratel 1 Reputation point

When trying to add a new scope to our DHCP Manager, I'm receiving the following error:
"The scope parameters are incorrect. Either the scope already exists or its subnet address and mask is inconsistent with the subnet address and mask of an existing scope."

I'd like to add the caveat that I'm not certain the existing scope was properly set up. It was set up years ago by someone who no longer works here. Here are the parameters of the scope I'm trying to add:

Start IP:
End IP:
Length: 26
Subnet mask:


Lease Duration: 8 days

Default Gateway:

Here are the properties of the existing Scope:
Start IP:
End IP:
Subnet Mask:
Lease Duration: 1 day

The existing scope is primarily used for dhcp reservations of devices, and I'm not convinced that it is set up properly.

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. Barzin Hosseini 81 Reputation points

    Hello .

    you need to change your new or existing subnet mask:

    Your Scope -> Usable Host IP : -
    Existing Scope -> Usable Host IP : -

    as you can see these scopes overlap.

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  2. Limitless Technology 37,771 Reputation points

    Hi there,

    In addition to the error message check the System and DHCP Server service event logs (Applications and Services Logs > Microsoft > Windows > DHCP-Server) for reported issues that are related to the observed problem.

    If you suspect that your existing scope is not set properly you can try to Install and Configure a DHCP Server in a Workgroup by following this article https://learn.microsoft.com/en-us/troubleshoot/windows-server/networking/install-configure-dhcp-server-workgroup

    Note that cannot add a DHCP reservation that is outside of the scope distribution range in Windows Server.

    If you receive an error while Modifying an existing DHCP scope ensure that the scope is expanded or contracted both ways or in one direction. Also, modify either the start or the endip address one at a time and immediately apply the changes after each and every change to the start or end ip address of the scope.


    --If the reply is helpful, please Upvote and Accept it as an answer–

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