Cisco 500 Series, Configuration Manual

Page: 171 / 1140

10-3
Cisco Security Appliance Command Line Configuration Guide
OL-12172-03
Chapter 10 Configuring DHCP, DDNS, and WCCP Services
Configuring a DHCP Server
Step 7
(Transparent Firewall Mode) Define a default gateway. To define the default gateway that is sent to
DHCP clients, enter the following command.
hostname(config)# dhcpd option 3 ip gateway_ip
If you do not use the DHCP option 3 to define the default gateway, DHCP clients use the IP address of
the management interface. The management interface does not route traffic.
Step 8
To enable the DHCP daemon within the security appliance to listen for DHCP client requests on the
enabled interface, enter the following command:
hostname(config)# dhcpd enable interface_name
For example, to assign the range 10.0.1.101 to 10.0.1.110 to hosts connected to the inside interface, enter
the following commands:
hostname(config)# dhcpd address 10.0.1.101-10.0.1.110 inside
hostname(config)# dhcpd dns 209.165.201.2 209.165.202.129
hostname(config)#
dhcpd wins 209.165.201.5
hostname(config)# dhcpd lease 3000
hostname(config)# dhcpd domain example.com
hostname(config)#
dhcpd enable inside
Configuring DHCP Options
You can configure the security appliance to send information for the DHCP options listed in RFC 2132.
The DHCP options fall into one of three categories:
• Options that return an IP address.
•
Options that return a text string.
• Options that return a hexadecimal value.
The security appliance supports all three categories of DHCP options. To configure a DHCP option, do
one of the following:
• To configure a DHCP option that returns one or two IP addresses, enter the following command:
hostname(config)# dhcpd option code ip addr_1 [ addr_2 ]
•
To configure a DHCP option that returns a text string, enter the following command:
hostname(config)#
dhcpd option
code
ascii
text
• To configure a DHCP option that returns a hexadecimal value, enter the following command:
hostname(config)# dhcpd option code hex value
Note The security appliance does not verify that the option type and value that you provide match the expected
type and value for the option code as defined in RFC 2132. For example, you can enter the
dhcpd option
46 ascii hello command and the security appliance accepts the configuration although option 46 is
defined in RFC 2132 as expecting a single-digit, hexadecimal value. For more information about the
option codes and their associated types and expected values, refer to RFC 2132.