Users Guide

Table Of Contents
Dell PowerConnect ArubaOS 5.0 | User Guide DHCP with Vendor-Specific Options | 597
Appendix A
DHCP with Vendor-Specific
Options
A standards-compliant DHCP server can be configured to return the host Dell controller’s IP address through the
Vendor-Specific Option Code (option 43) in the DHCP reply. In the Dell user-centric network, this information
can allow an Dell AP to automatically discover the IP address of a master controller for its configuration and
management. This appendix describes how to configure vendor-specific option 43 on various DHCP servers.
This appendix contains the following topics:
z “Overview” on page597
z “Windows-Based DHCP Server” on page597
z “Linux DHCP Servers” on page599
Overview
DHCP servers are a popular way of configuring clients with basic networking information such as an IP address, a
default gateway, network mask, DNS server, and so on. Most DHCP servers have the ability to also send a variety
of optional information, including the Vendor-Specific Option Code, also called option 43.
Here is how option 43 works:
1. The DHCP client on an Dell AP adds an optional piece of information called the Vendor Class Identifier
Code (option 60) to its DHCP request. The value of this code is ArubaAP.
2. The DHCP server sees the Vendor Class Identifier Code in the request and checks to see if it has option 43
configured. If it does, it sends the Vendor-Specific Option Code (option 43) to the client. The value of this
option is the loopback address of the Dell master controller.
3. The AP receives a response from the DHCP server and checks if option 43 is returned. If it is, the AP contacts
the master controller using the supplied IP address.
Windows-Based DHCP Server
Configuring a Microsoft Windows-based DHCP server to send option 43 to the DHCP client on an Dell AP
consists of the following two tasks:
z Configuring Option 60
z Configuring Option 43
Configuring Option 60
This section describes how to configure the Vendor Class Identifier Code (option 60) on a Microsoft Windows-
based DHCP server.
As mentioned in the overview section, option 60 identifies and associates a DHCP client with a particular vendor.
Any DHCP server configured to take action based on a client’s vendor ID should also have this option configured.
Since option 60 is not a predefined option on a Windows DHCP server, you must add it to the option list for the
server.