DHCP Vendor Options

In addition to DHCP standard and custom options, you can configure up to 255 vendor-specific options. Vendor-specific options always transmit within a single DHCP Option 43.

You can use the ip dhcp-server vendor-option-def and ip dhcp-server vendor-option-data commands to configure the vendor-specific options to always transmit in DHCP Offer, as shown in the following example configuration:

ip dhcp-server vendor-option-def 1 type ipv4-address
ip dhcp-server vendor-option-data 1 value 192.0.2.24

However, different client types expect to find different information within Option 43. These clients advertise which type of device they are in DHCP Option 60 so it is more common to specify a vendor-specific option conditional upon a match of a specific client type from Option 60.

In the following configuration example, vendor-specific information transmits within Option 43 if the client reports itself as "WingAP.AP510" in Option 60.

ip dhcp-server vendor-option-def 1 type string name XIQ-Controllers
ip dhcp-server vendor-class 1 matches "WingAP.AP510"
ip dhcp-server vendor-class 1 vendor-option-data 1 value "192.0.2.146,192.0.2.143"
 

The vendor-option ID is encoded within Option 43. Multiple vendor-option IDs (up to 255) can be included within the same Option 43. The vendor-class ID is not encoded in any DHCP packet and serves only to link a vendor-option value with a conditional match of an Option 60 device type. The conditional sending of DHCP options can also be used with standard and custom DHCP options.

The configuration shown in the following example, transmits vendor-specific information within Option 43 for clients that report as "IOT.Bot" in Option 60, and sends DHCP standard options to configure the TFTP server IP and Domain-Name, as well as a custom-option 224, which includes an IP address for an IOT Controller:

ip dhcp-server vendor-option-def 1 type string name IOT-Controller
ip dhcp-server custom-option-def 224 type ipv4-address name IOT-collection-server
ip dhcp-server vendor-class 1 matches "IOT.Bot"
ip dhcp-server vendor-class 1 vendor-option-data 1 value 192.0.2.146
ip dhcp-server vendor-class 1 domain-name mydomain.com
ip dhcp-server vendor-class 1 tftp server-ip 192.0.2.24
ip dhcp-server vendor-class 1 custom-option-data 224 value 203.0.113.21

The following list provides valid data types for vendor-options and custom-options:

For more information about the different scopes and their precedence in application, see DHCP Server.