18-4
Cisco ASA 5500 Series Configuration Guide using ASDM
Chapter18 Configuring DHCP
Configuring DHCP Relay Services
Editing DHCP Relay Agent Settings
You can enable the DHCP relay agent and configure the relay agent parameters for the selected interface.
Restrictions
•You cannot enable a DHCP relay agent on an interface that has a global DHCP relay server
configured for it.
•You cannot enable a DHCP relay agent on an ASA that has a DHCP server configured on an
interface.
Prerequisites
Before you can enable a DHCP relay agent on an selected interface, you must have at least one global
DHCP relay server in the configuration.
To modify DHCP Relay Agent Settings, perform the following steps:
Step1 To enable the DHCP relay agent on the selected interface, check the Enable DHCP Relay Agent check
box. You must have a global DHCP relay server defined before enabling the DHCP relay agent.
Step2 To specify whether the DHCP relay agent is configured to modify the default router address in the
information returned from the DHCP server, check the Set Route check box. The DHCP relay agent then
substitutes the address of the selected interface for the default router address in the information returned
from the DHCP server.
Step3 To add or edit global DHCP relay server settings, see the “Configuring DHCP Relay Services” section
on page 18-2.
Adding or Editing Global DHCP Relay Server Settings
You can define new global DHCP relay servers or edit existing server information. You can define up to
four global DHCP relay servers.
Restrictions
You cannot define a global DHCP relay server on an interface that has an enabled DHCP server.
To add a global DHCP relay server to which DHCP requests will be relayed, perform the following steps:
Step1 In the Global DHCP Relay Servers area, click Add to display the Add Global Relay Servers dialog box.
Step2 In the DHCP Server field, enter the IP address of the external DHCP server to which DHCP requests are
forwarded, or click the ellipses to display the Browse DHCP Server dialog box.
Step3 To continue, see Step4 of “Configuring a DHCP Server” section on page 18-5.
Step4 Choose the interface through which DHCP requests are forwarded to the external DHCP server from the
drop-down list.
Step5 Click OK to close the Add Global Relay Servers dialog box. The newly added global DHCP relay server
appears in the list.
Step6 To modify global DHCP relay server settings, click Edit to display the Edit DHCP Global Relay Servers
dialog box.