Security Considerations; Using The Gui To Configure Dhcp - Cisco 2100 Series Configuration Manual

Chapter 6 Configuring WLANsWireless Device Access
Per-WLAN Assignment
You can also define a DHCP server on a WLAN. This server will override the DHCP server address on
the interface assigned to the WLAN.

Security Considerations

For enhanced security, Cisco recommends that you require all clients to obtain their IP addresses from
a DHCP server. To enforce this requirement, all WLANs can be configured with a DHCP Addr.
Assignment Required setting, which disallows client static IP addresses. If DHCP Addr. Assignment
Required is selected, clients must obtain an IP address via DHCP. Any client with a static IP address is
not be allowed on the network. The controller monitors DHCP traffic because it acts as a DHCP proxy
for the clients.
WLANs that support management over wireless must allow management (device-servicing) clients to
Note
obtain an IP address from a DHCP server. See the
page 5-52
If slightly less security is tolerable, you can create WLANs with DHCP Addr. Assignment Required
disabled. Clients then have the option of using a static IP address or obtaining an IP address from a
designated DHCP server.
You are also allowed to create separate WLANs with DHCP Addr. Assignment Required disabled; then
define the primary / secondary DHCP server as 0.0.0.0 on the interface assigned to the WLAN. These
WLANs drop all DHCP requests and force clients to use a static IP address. Note that these WLANs do
not support management over wireless connections.
Refer to
Note
This section provides both GUI and CLI instructions for configuring DHCP.

Using the GUI to Configure DHCP

Follow these steps to configure DHCP using the GUI.
Follow the instructions in the
Step 1
Service-Port Interfaces" section on page 3-11
section on page 3-16
interface that will be assigned to the WLAN.
Note
Click WLANs to open the WLANs page.
Step 2
Click the ID number of the WLAN for which you wish to assign an interface. The WLANs > Edit
Step 3
(General) page appears.
On the General tab, uncheck the Status check box and click Apply to disable the WLAN.
Step 4
Re-click the ID number of the WLAN.
Step 5
OL-17037-01
for instructions on configuring management over wireless.
Chapter 4 for instructions on globally configuring DHCP proxy.
"Using the GUI to Configure the Management, AP-Manager, Virtual, and
to configure a primary DHCP server for a management, AP-manager, or dynamic
When you want to use the internal DHCP server, you must set the management interface IP
address of the controller as the DHCP server IP address.
"Using Management over Wireless" section on
or "Using the GUI to Configure Dynamic Interfaces"
Cisco Wireless LAN Controller Configuration Guide
Configuring WLANs
6-9