> For the complete documentation index, see [llms.txt](https://cortex-docs.paloaltonetworks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cortex-docs.paloaltonetworks.com/cortex-xpanse/inventory/manage-business-units/create-a-user-defined-ipv4-range.md).

# Create a user-defined IPv4 range

You can modify the business unit (BU) assignments for system-defined owned IPv4 ranges and other assets in Expander. You can also create user-defined IPv4 ranges to reassign to different BUs.

Changes to BU assignments may take up to an hour to appear in alerts and incidents.

1. Navigate to **Inventory** → **Owned IPv4 Ranges**.
2. Click the **Reassign Range** button at the top right side of the page.
3. In the **Edit Asset Business Unit Tags** dialog, select one of the following options and enter the IP addresses as appropriate:
   * **Edit Business Units for a subset IP Range**—modifies the BUs for a user-defined IP range that you define.

     Enter the Starting IP Address and Ending IP Address to define the new range. You can also define the range in CIDR format. Click **Next**.
   * **Edit Business Units for a single IP address**—modifies the BU for a single IP address.

     Enter the IP address. Click **Next**.
4. Add or remove BUs by selecting or deselecting them in the list.

   ![add-bu-screen.png](/files/VknvVDUxk5MhQKlnlz3D)
5. Add a comment in the **Change Reason** box explaining why the change was made, then click **Next**.
6. Select how you want to handle conflicts with previously-defined ranges by choosing to **Keep previously-applied business units** or **Replace all previously-applied business units**. If you choose to replace, confirm your choice by entering **REPLACE** in the dialog box.

   This step applies only if there are conflicts with previous-defined ranges with different BU assignments.

   ![resolve-conflicting-ranges.png](/files/102RUGcHhOmhFCvAGQyW)
7. Review the final list of business units to be assigned to the new range. Also review the specific impacts this change will have on scope-based user access. Click **Apply**.

   Note that the change may impact user access to incidents, alerts, and services in addition to the asset.

**Delete a user-defined IPv4 range**

When you delete a user-defined IPv4 range, the IP addresses revert back to the Cortex Xpanse-defined parent ranges that they were originally part of. Any business units, tags, or notes that were added to the user-defined IPv4 range are removed, and the business units, tags, and notes from the parent range are applied.

Perform the following steps to delete a user-defined IPv4 range:

1. Navigate to **Inventory** → **IPv4 Ranges**.
2. Click on the user-defined range to be deleted. The details panel will open on the right side of the page.
3. Click the delete icon ![delete.png](/files/fJAjltc6TJdTHpuoLAia) at the top right side of the details panel.
4. In the Delete IP Range Reassignment dialog box, verify that you are deleting the correct range. Click **Delete Range Reassignment**.


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