Configuring Dhcp Option 82 - Cisco 2100 Series Configuration Manual

Chapter 5 Configuring Security Solutions
Use a wireless client to associate with an access point connected to the controller that you want to
Step 3
manage.
Step 4 Enter telnet controller-ip-address and log into the CLI to verify that you can manage the WLAN using
a wireless client.

Configuring DHCP Option 82

DHCP option 82 provides additional security when DHCP is used to allocate network addresses.
Specifically, it enables the controller to act as a DHCP relay agent to prevent DHCP client requests from
untrusted sources. The controller can be configured to add option 82 information to DHCP requests from
clients before forwarding the requests to the DHCP server. See
process.
Figure 5-28
PC or PDA with 802.11
Client and IP Soft-Phone
The access point forwards all DHCP requests from a client to the controller. The controller adds the
DHCP option 82 payload and forwards the request to the DHCP server. The payload can contain the
MAC address or the MAC address and SSID of the access point, depending on how you configure this
option.
In order for DHCP option 82 to operate correctly, you must enable DHCP proxy, which is disabled by
Note
default. Refer to the
DHCP proxy.
Any DHCP packets that already include a relay agent option are dropped at the controller.
Note
DHCP option 82 is not supported for use with auto-anchor mobility, which is described in
Note
OL-17037-01
DHCP Option 82
Access
Point
802.11 WLAN
IP Phone
"Configuring DHCP Proxy" section on page 4-22
Controller adds Option 82
payload to the request
and forwards it to DHCP Server
DHCP
Relay Agent
(Controller)
Cisco Wireless LAN Controller Configuration Guide
Configuring DHCP Option 82
Figure 5-28 for an illustration of this
IP
for instructions on configuring
DHCP
Server
Chapter 12.
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