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Cisco ASA 5500 Series Configuration Guide using ASDM
Chapter18 Configuring DHCP
Configuring a DHCP Server
e. The duration of time that the DHPC server configured on the interface allows DHCP clients to use
an assigned IP address.
f. The interface on a DHCP client that provides DNS, WINS, and domain name information for
automatic configuration.
Step7 To configure more DHCP options, click Advanced to display the Advanced DHCP Options dialog box.
For more information, see the “Configuring Advanced DHCP Options” section on page 18-7.
Step8 Click OK to close the Edit DHCP Server dialog box.
Step9 Click Apply to save your changes, or click Reset to discard them and enter new ones.
Configuring Advanced DHCP Options
You can use advanced DHCP options to provide DNS, WINS, and domain name parameters to DHCP
clients. You can also use the DHCP automatic configuration setting to obtain these values or define them
manually. When you use more than one method to define this information, it is passed to DHCP clients
in the following sequence:
1. Manually configured settings.
2. Advanced DHCP options settings.
3. DHCP automatic configuration settings.
For example, you can manually define the domain name that you want the DHCP clients to receive, and
then enable DHCP automatic configuration. Although DHCP automatic configuration discovers the
domain together with the DNS and WINS servers, the manually-defined domain name is passed to DHCP
clients with the discovered DNS and WINS server names, because the domain name discovered by the
DHCP automatic configuration process is superseded by the manually-defined domain name.
To configure advanced DHCP options, perform the following steps:
Step1 In the Option to be Added area, define the following settings:
a. Choose the option code from the drop-down list. All DHCP options (options 1 through 255) are
supported except 1, 12, 50–54, 58–59, 61, 67, and 82.
b. Choose the options that you want to configure. Some options are standard. For standard options, the
option name is shown in parentheses after the option number and the option parameters are limited
to those supported by the option. For all other options, only the option number is shown and you
must choose the appropriate parameters to supply with the option. For example, if you choose DHCP
Option 2 (Time Offset), you can only supply a hexadecimal value for the option. For all other DHCP
options, all of the option value types are available and you must choose the appropriate options value
type.
c. In the Option Data area, specify the type of information that the option returns to the DHCP client.
For standard DHCP options, only the supported option value type is available. For all other DHCP
options, all of the option value types are available. Click Add to add the option to the DHCP option
list. Click Delete to remove the option from the DHCP option list.
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Click IP Address to indicate that an IP address is returned to the DHCP client. You can specify
up to two IP addresses. IP Address 1 and IP Address 2 indicate an IP address in dotted-decimal
notation.