---
title: "Creating IPv4 Hardware Filters"
canonical: "https://docs.infoblox.com/space/BloxOneDDI/186466697/Creating%20IPv4%20Hardware%20Filters"
format: markdown
---
You can define the Hardware Operator option and add it as a match rule to an option filter. This option enables Universal DDI to match the hardware type and MAC address of the DHCP client, which it derives from the hardware type, hlen (hardware length) and chaddr (client hardware address) fields of the client’s DHCP Discover and Renew packets.
To define an IPv4 hardware filter:
1. From the Infoblox Portal, click **Network** > **DHCP **>** Filters** > **Create,** and select **IPv4 Hardware Filter **from the drop-down list.
2. On the *Create IPv4 Hardware Filter* page, specify the following:
- **Name**: Enter a meaningful name for the hardware filter.
- **Description**: Enter additional information about the filter.
- **Role**: Choose the appropriate role for this filter:
- **Option Values (Assign various options)**: Option values are configuration settings that the server assigns to clients along with an IP address lease. These options provide essential information that allows the client to communicate properly within the network. Each option is identified by a numeric code and delivers specific parameters such as the default gateway, DNS servers, domain name, and more. For example, *Option 3* specifies the default gateway, such as `192.168.1.1`, which tells the client where to send packets destined for external networks. *Option 6* defines DNS servers, such as `8.8.8.8` and `8.8.4.4`, which the client will use to resolve domain names to IP addresses. Similarly, *Option 15* might specify the local domain name, like [corp.example.com](http://corp.example.com). By assigning these option values, administrators can automatically and consistently configure network settings across all DHCP-enabled devices without manual intervention.
- **Selection (Control client access to DHCP pools): **Selection refers to the method used by the DHCP server to control which clients are allowed to access specific address pools. This selection process is typically based on attributes such as the client’s MAC address, vendor class identifier, or relay agent information. It enables administrators to apply policies and assign IP addresses from predefined pools based on the client’s identity or role. For example, IP phones with a vendor class identifier of `IPPhone` might be assigned addresses from the `192.168.10.0/24` pool, while corporate laptops could be directed to a different pool like `192.168.20.0/24` based on their MAC address range. This approach enhances network segmentation, improves security, and ensures efficient use of IP address space by aligning address assignment with the organization’s topology and policies.
- **Tags**: For information about tags, see *[Managing Tags](https://infoblox-docs.atlassian.net/wiki/spaces/BloxOneDDI/pages/186745865)*.
- In the **MAC** addresses panel, click **Add** to add a Mac address to the list or click **Remove** to delete the entry:
- **MAC ADDRESS**: You can use MAC address for option filters to classify DHCP clients and decide which DHCP options each group of clients can receive. You can use wildcard while specifying the MAC address. For example, you can use 00:00:5E:00:53:*.
- **Lease Time**: This field is visible only if you select **Option Values (Assign various options)**. Enter the lease time and select the time unit from the drop-down list. The maximum lease time allowed is 5 years. Universal DDI will now automatically convert imported unlimited DHCP lease times to the maximum supported by the systems, which is 5 years.
- **DHCP Options**: This field is visible only if you select **Option Values (Assign various options)**. In the **DHCP Options** panel, click **Add** to add a DHCP option space or an option group to the list or click **Remove** to delete the entry:
- **Type**: Select **Option** or **Option Group** based on what you want to add to the list.
- **Space**: Select a value from the drop-down list. The list displays either option spaces or option groups based on the **Type** you select.
- **Name**: Select a value from the drop-down list. The list displays names of the option spaces or option groups based on the **Space** you select.
- **Option** **Type**: Displays the option type.
- **Value**: Enter the match value that you want the filter to use for the selected DHCP option. To add more options to the filter, click **Add** and repeat the steps.
3. Configure the Header Options. To obtain the configuration, some devices use one or more of the following fields in the DHCPv4 packet: next-server, server-NIOS-X Server name, and boot-file-name. Configure the following:
- **Server Name**: Specify the server's NIOS-X Server name, which can be up to 64 bytes long.
- **File Name**: Specify the configuration file's name, which can be up to 128 bytes long.
- **Server Address**: Specify the IPv4 address.
4. Configure the Vendor Encapsulated Option Space. The vendor encapsulated option space is available, which is option 43.
- **Option Space (43)**: You can specify the hexadecimal value while creating the option space or create an encapsulated option space.
- **Hexadecimal in an Option Space**: For **Type**, select **Option**. For **Space**, select the option space you have created. For more information on option spaces, see *[Creating Option Spaces](https://infoblox-docs.atlassian.net/wiki/spaces/BloxOneDDI/pages/186681347)*. Create an option space with **Type** as hexadecimal. If you choose the **Option Type** as hexadecimal, specify the value as **aa:bb:cc**, **aa-bb-cc**, or **aabbcc**.
5. Click **Save & Close** to save the details or click **Cancel** to exit.
> ⚠️ The lease time at the filters does not function properly for IPv6 filters and filters associated with a subnet due to a bug in Kea. Once the bug is fixed by ISC, Universal DDI will be updated with a patch for the feature to function properly.