How to configure the DHCP server on a Cisco ASA device?  

DHCP (Dynamic Host Configuration Protocol) servers provide all the basic information the client wants to operate on the network, including DNS address, Default Gateway, IP addresses, and subnet. masks and many more.

In this blog, we configure the Cisco ASA firewall to act as a DHCP (Dynamic Host Configuration Protocol) server. DHCP simplifies the process of IP address assignment in your network. In this scenario, we’ll set up the ASA to provide IP addresses to internal LANs using different DHCP scopes.

let's see the configuration: 

Topology:-

• configure the topology as per the diagram 
• configure the IP addresses on ASA and configure security
• configure DHCP server on ASA 
• verify the configuration with show commands and ping. 

ciscoasa(config)# interface gigabitEthernet 0

ciscoasa(config-if)# ip address 192.168.1.1 255.255.255.0

ciscoasa(config-if)# security 100

ciscoasa(config-if)# nameif inside

ciscoasa(config-if)# no shutdown

ciscoasa(config-if)# exit

ciscoasa(config)# dhcpd address 192.168.1.2-192.168.1.240 inside

ciscoasa(config)# dhcpd dns 8.8.8.8

ciscoasa(config)# dhcpd domain internetworks

ciscoasa(config)# dhcpd option 3 ip 192.168.1.1

ciscoasa(config)# dhcpd lease 3000

ciscoasa(config)# dhcpd enable inside

ciscoasa(config)# exit

ciscoasa# show dhcpd binding

IP address       Client Identifier        Lease expiration        Type

    192.168.1.2    0100.5079.6668.00            2399 seconds    Automatic

    192.168.1.3    0100.5079.6668.01            2941 seconds    Automatic

    192.168.1.4    0100.5079.6668.02            2949 seconds    Automatic

    192.168.1.5    0100.5079.6668.03            2956 seconds    Automatic

    192.168.1.6    0100.5079.6668.04            2963 seconds    Automatic

    192.168.1.7    0100.5079.6668.05            2970 seconds    Automatic

    192.168.1.8    0100.5079.6668.06            2977 seconds    Automatic

ciscoasa# show dhcpd statistics

DHCP UDP Unreachable Errors: 0

DHCP Other UDP Errors: 0

Address pools        1

Automatic bindings   7

Expired bindings     0

Malformed messages   0

Message              Received

BOOTREQUEST          0

DHCPDISCOVER         7

DHCPREQUEST          14

DHCPDECLINE          0

DHCPRELEASE          0

DHCPINFORM           0

Message              Sent

BOOTREPLY            0

DHCPOFFER            7

DHCPACK              14

DHCPNAK              0

ciscoasa# show dhcpd state

Context  Configured as DHCP Server

Interface inside, Configured for DHCP SERVER

PC2> ip dhcp

DORA IP 192.168.1.3/24 GW 192.168.1.1

PC2> show ip

NAME        : PC2[1]

IP/MASK     : 192.168.1.3/24

GATEWAY     : 192.168.1.1

DNS         : 8.8.8.8

DHCP SERVER : 192.168.1.1

DHCP LEASE  : 2565, 3000/1500/2625

DOMAIN NAME : internetworks

MAC         : 00:50:79:66:68:01

LPORT       : 10017

RHOST:PORT  : 127.0.0.1:10018

MTU:        : 1500