Documentation forIP Address Manager

Define scope options on a DHCP server

IPAM supports the majority of DHCP scope options defined within the RFC 2132 standard. The Scope Options tab is available when creating or editing a scope.

The available options vary depending on the server vendor. Click Add option to add options.

Set up VoIP options (66 and 67) on your scopes.

Custom DHCP options (codes 128–254)

IPAM supports vendor-specific / site-specific DHCP options in the private-use range defined by RFC 2132 (option codes 128 through 254). Before IPAM can scan, display, or manage a custom option on a DHCP server, you must first declare it in IPAM so the system knows the option code, data type, and which server types it applies to.

Supported server types

Custom DHCP options are supported differently depending on the DHCP server type.

Server Type Scan (read) Create/Edit scope (write)
ISC Full support Full support
Kea Full support Full support
Cisco Full support (IPv4 only) Full support (IPv4 only)
Windows Full support Full support

Supported data types

When declaring a custom option, you choose a data type. The available types depend on the selected server type(s).

Data Type Windows ISC Kea Cisco
IP address Y Y Y Y
IP address array Y Y Y Y
IPv6 address Y Y Y N
IPv6 address array Y Y Y N
String Y Y Y Y
Boolean (Byte) Y Y Y Y
Long Y Y Y Y
Integer Y Y Y Y
Small integer Y Y Y Y
Integer array Y Y Y N
Binary array (hex) Y Y Y Y
String array Y N N N

How to declare a custom option

  1. Navigate to DHCP & DNS Management > DHCP Scopes.

  2. In the Add New Custom Option section, fill in:

    • Option Code (128–254) — The numeric option code. Must match the code configured on your DHCP server.

    • Description — A short name for the option (maximum 150 characters). This label appears in the scope options list when creating or editing a scope.

    • Option Type — The data type of the option value. Must match the type defined on the DHCP server. The list of available types is filtered based on the selected server types.

    • Applies To — Select whether the option applies to Both (IPv4 and IPv6), IPv4 only, or IPv6 only.

    • Server Types — Check one or more: Windows, ISC, Kea, Cisco. At least one must be selected.

    • Default Value (optional) — A default value pre-filled when adding this option to a scope.

    • Help Text (optional) — Additional guidance text shown to users when they configure this option on a scope (maximum 2048 characters).

  3. Click Close to dismiss the dialog.

How to delete a custom option

In the Manage Custom DHCP Options dialog, click the Delete button next to the option you want to remove. Deleting a custom option definition also removes all stored option values for that code across all scopes.

Deleting a custom option definition removes the option values from all scopes that use it. This action cannot be undone.

Using custom options on scopes

After declaring a custom option in IPAM:

  1. Scan the server — Trigger a DHCP server scan (or wait for the next scheduled scan). IPAM reads option values from the server configuration and matches them against declared custom option codes. Only values whose data type is compatible with the declaration are imported.

  2. View on scope — After the scan completes, navigate to a scope, select it, and click Edit. Custom options that were found on the server appear alongside standard options on the Options step.

  3. Add to a new or existing scope — When creating or editing a scope, click Add option in the Edit DHCP scope > Options tab. Declared custom options appear in the dropdown list with their description and code. Set the value and save.

Unsupported DHCP options

The following options are unsupported:

Unsupported Windows DHCP Server options

  • 39 TCP Keepalive Data
  • 58 Renewal Time Value
  • 59 Rebinding Time Value
  • There is no UI option to create option 58 and 59 on a Windows DHCP server. They are simply a function of lease time (option 51).

Unsupported Cisco DHCP Server options

  • 12 Host Name
  • 50 Address Request
  • 52 Overload
  • 53 DHCP Msg Type
  • 54 DHCP Server Id
  • 58 Renewal Time
  • 59 Rebinding Time
  • 61 Client Id

Unsupported ISC DHCP server options

  • 50 Address Request
  • 53 DHCP Message Type
  • 54 DHCP Server Identifier
  • 56 DHCP Message
  • 58 Renewal Time
  • 59 Rebinding Time

Unsupported Kea DHCP server options

  • IPv4
    • 43 vendor-encapsulated-options
    • 122 cablelabs-client-conf
  • IPv6
    • 66 rsoo
    • 94 s46-cont-mape
    • 95 s46-cont-mapt
    • 96 s46-cont-lw