DHCP SERVICES In Cisco ASA

DHCP SERVICES In Cisco ASA

The appliances support many DHCP services, including being a DHCP server and/or
client as well as relaying DHCP client requests for addressing information on one interface
to a second interface that has a DHCP server connected to it. This is similar to the
IOS IP Helper feature.

DHCP Server Configuration :-

The following commands are used to configure the appliance as a DHCP server:


ciscoasa(config)# dhcpd address IP_address-IP_address logical_if_name
ciscoasa(config)# dhcpd domain domain_name
ciscoasa(config)# dhcpd dns dns_IP_1 [dns_IP_2]
ciscoasa(config)# dhcpd wins wins_IP_1 [wins_IP_2]
ciscoasa(config)# dhcpd lease lease_length
ciscoasa(config)# dhcpd ping_timeout milliseconds
ciscoasa(config)# dhcpd option option_number ip IP_address
ciscoasa(config)# dhcpd auto_config logical_if_name [[vpnclient-wins-override]
interface logical_if_name]
ciscoasa(config)# dhcpd enable logical_if_name

DHCP Server Verification :-

The show dhcpd command displays the address bindings and statistics for the DHCP
server:
ciscoasa# show dhcpd {binding [IP_address] | state | statistics}

Here’s an example of the use of this command, which displays the IP addresses assigned
to requesting users:


ciscoasa# show dhcpd binding
IP Address Hardware Address Lease Expiration Type
10.0.1.101 0100.a0d4.e834 84985 seconds automatic


In this example, only one address has been assigned to a client.

DHCP Server Configuration Example :-

Here’s a simple DHCP server configuration where the appliance is assigning itself as the
default gateway (10.0.1.1) for the inside interface:
ciscoasa(config)# dhcpd address 10.0.1.200-10.0.1.254 inside
ciscoasa(config)# dhcpd domain dealgroup.com
ciscoasa(config)# dhcpd dns 4.2.2.2
ciscoasa(config)# dhcpd ping_timeout 500
ciscoasa(config)# dhcpd option 3 ip 10.0.1.1
ciscoasa(config)# dhcpd enable inside