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User Guide for Cisco Security Manager 4.4
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Chapter 51 Configuring Server Access Settings on Firewall Devices
Configuring DHCP Servers
If your firewall is also acting as a DHCP client on the outside interface, you can enable auto-negotiated
IP configuration. This allows the firewall to pass the DNS, WINS and domain name parameters it gets
from the outside interface (as a DHCP client) to hosts on its inside network. Alternatively, you can
manually specify the DNS, WINS and domain name parameters. If you specify those parameters
manually and auto-configuration is on, your values take precedence over auto-configuration.
Use the DHCP Server Page, page 51-10 to manage DHCP server definitions.
DHCP Server Page
Use the DHCP Server page to configure global DHCP server and dynamic DNS (DDNS) update options,
to set up a DHCP server on one or more device interfaces, and to configure advanced server options.
Navigation Path
•(Device view) Select Platform > Device Admin > Server Access > DHCP Server from the Device
Policy selector.
•(Policy view) Select PIX/ASA/FWSM Platform > Device Admin > Server Access > DHCP
Server from the Policy Type selector. Select an existing policy from the Shared Policy selector, or
create a new one.
Related Topics
•Configuring DHCP Servers, page 51-9
Field Reference
Table51-9 DHCP Server Page
Element Description
Ping Timeout Specify the amount of time, in milliseconds, that the firewall device
waits to time out a DHCP ping attempt. To avoid address conflicts,
firewall devices send two ICMP ping packets to an address before
assigning that address to a DHCP client. Valid values range from 10 to
10000 milliseconds.
Lease Length Specify the amount of time, in seconds, that the client can use its
allocated IP address before the lease expires. Valid values range from
300 to 1048575 seconds. The default value is 3600 seconds (1 hour).
Enable auto-configuration
(PIX and ASA only)
Select this option to enable DHCP auto configuration.
DHCP auto configuration causes the DHCP server to provide DHCP
clients with DNS server, domain name, and WINS server information
obtained from a DHCP client running on the specified interface. If any
of the information obtained through auto configuration is also specified
manually, the manually specified information takes precedence over the
discovered information.
Interface If Enable auto-configuration is checked, this field is available. Enter or
Select the interface running the DHCP client that supplies the DNS,
WINS, and domain name parameters.
Define settings (optional)
Domain Name Specify the DNS domain name for DHCP clients. Enter a valid DNS
domain name; for example, example.com.