Custom options under Microsoft DHCP

In Microsoft DHCP, custom options provide network administrators with the flexibility to tailor DHCP services to meet specific needs beyond the predefined options. These custom options allow for more granular control and the ability to configure unique parameters for DHCP clients. Here’s an overview of the custom options available in Microsoft DHCP:

Overview of Custom Options

Custom options in Microsoft DHCP are additional DHCP options that can be defined and assigned to DHCP clients beyond the standard options predefined by the DHCP protocol. These options allow for more tailored and specific network configuration settings tailored to unique needs that may not be covered by the standard set.

These user-defined settings can be added to DHCP scopes or policies to deliver specific configuration parameters to DHCP clients. These options are identified by unique option codes and can carry various types of data, such as strings, IP addresses, or binary data.

Creating Custom Options

Steps to create Custom Options:

• Get into the DHCP module.
• Navigate to DHCP-> Config-> Custom Options.
• Find the green add button adjacent to the Options drop-down list.
• The Add Definition form appears. Here, enter the essential details to define Custom options for your requirements.



• Name: Provide a descriptive name for the custom option.
• Data Type: Select the appropriate data type (e.g., IP Address, String, Binary, DWORD).
Note: A DWORD, or Double Word, is a data type in computing that typically represents a 32-bit unsigned integer. In simpler terms, it's a way of storing numerical values that can range from 0 to 4,294,967,295.
• Code: Assign a unique option code (between 1 and 255 for IPv4, and 1 and 65535 for IPv6).
  Note: 1 to 77 are already taken, hence a value above 78 and above are recommended for the custom options you define.
• Description: Optionally, provide a brief description of the custom option’s purpose.
• Specify the Vendor class to categorize it under a specific Vendor class.
• Click Save to finalize the Custom option definition.
• Once the custom option is defined, it can be assigned to a DHCP scope or policy or retained at the global level by default.

• To specifically implement the custom options at the global, scope, or policy level.

  Scope level: Navigate to DHCP-> Network->Subnet. Open the subnet of your choice in the Edit mode or create one. Find the Custom Options tab at the extreme bottom. Select the relevant vendor class and select the custom DHCP options defined within it from the Options drop-down list.

  Policy level: Navigate to DHCP-> Network->Policy. Open the Policy of your choice in the Edit mode or create one. Find the Custom Options tab at the extreme bottom. Select the relevant vendor class and select the custom DHCP options defined within it from the Options drop-down list.

  Global level: Navigate to DHCP-> Network->Config. Select the Config menu within the DHCP module to program the DHCP global level configurations. On the Configuration page, navigate to the Custom Options tab. Select the relevant vendor class and select the custom DHCP options defined within it from the Options drop-down list.

Benefits of Custom Options

• Flexibility: Custom options provide the ability to meet specific network requirements not covered by standard DHCP options.
• Granularity: Allows for fine-tuned configuration settings tailored to different groups of clients or devices.
• Enhanced Control: Improves overall network management by enabling the delivery of precise configuration parameters.

Considerations

• Compatibility: Ensure that DHCP clients support the custom options being configured.
• Uniqueness: Use unique option codes to prevent conflicts with predefined options.

By leveraging custom options in Microsoft DHCP, network administrators can achieve greater control and customization, ensuring that DHCP clients receive the exact configuration they need for optimal operation within the network.