--- title: "Creating Option Filters" canonical: "https://docs.infoblox.com/space/BloxOneDDI/186648616/Creating%20Option%20Filters" format: markdown --- To create an IPv4 option filter: 1. From the Infoblox Portal, click **Network > DHCP > Filters > Create Option Filter,** and select **IPv4 Option Filter or IPv6 Option Filter **from the drop-down list. 2. On the **Create Option Filter **page, specify the following: - **Name**: Enter a meaningful name for the option filter. For example, you can enter Linux if you plan to use this option filter to screen Linux systems. If you want to specify option settings in the filter, the filter name must be unique among all option filters. - **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 **Rules** panel, select **Any **or **All **from the **Match **drop-down list to match any rule or all rules in the list. Click **Add** to add a DHCP option rule to the list or click **Remove** to delete the entry: - **CODE**: Click the down arrow and select an option space from the drop-down list. The selected option space contains the corresponding DHCP options that you can use as filter criteria. - **v4-mac-address(256)**: This feature enhances DHCP option filters by enabling MAC address-based matching within option filter classes, allowing more precise control over how DHCP options are assigned to devices with fixed addresses. It supports the use of multiple filters that evaluate both MAC addresses and specific DHCP option values (such as vendor-class-identifier or user-class), enabling a device to receive different DHCP options based on its current boot state, while retaining the same IP and MAC address. This is achieved by introducing a new internal option code, option 256 for MAC address, used specifically for filtering purposes. Choose the Operator from the drop-down. Specify the MAC address in the drop-down. This feature is only applicable to IPv4 networks. A large number of MAC address filters may reduce DHCP performance. - - **OPERATOR**: Click the down arrow and from the drop-down list, select an operator. If you select **Equals** or **Not Equals**, enter the value of the selected option you want the filter to match in the field. - **VALUE**: Enter the match value that you want the filter to use for the selected DHCP option. - **OFFSET**: Enter the number of characters at which the match value substring starts in the option data. Enter 0 to start at the beginning of the option data, enter 1 for the second position, and so on. For example, when you enter 2 and have a match value of MSFT, the appliance matches the value MSFT starting at the third character of the option data. - **Lease Time**: 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. - In the **DHCP Options** panel, complete the following to define which DHCP options to return to the matching client: - **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. This setting is only available for IPv4 option filters. 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. This setting is only available for IPv4 option filters. The vendor encapsulated option space is available, which is option 43. - **vendor-encapsulated-options(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.