ip dhcp excluded 192.168.0.1 （排除的IP）
ip dhcp pool xxx（隨便你定義的名字）
network 192.168.0.0 255.255.255.0 （你分配的IP段）
default-router 192.168.0.1 （關網的網內）
dns-server 202.96.64.68 （DNS伺服器的IP）
lease 7
netbios-name-server

Router>en
Password:
Router#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)#ip dhcp excluded 10.10.0.1 10.10.0.254
Router(config)#ip dhcp pool office
Router(dhcp-config)#network 10.10.0.0 255.255.255.0
Router(dhcp-config)#default-router 10.10.0.254
Router(dhcp-config)#dns-server 208.67.222.222 208.67.220.220
Router(dhcp-config)#netbios-name-server 10.10.0.2
Router(dhcp-config)#lease 7
Router(dhcp-config)#end
Router#
		
		

可變長子網掩碼實例

		
ip dhcp excluded-address 192.168.40.250 192.168.40.254
ip dhcp excluded-address 192.168.50.250 192.168.50.254
!
ip dhcp pool Office-1
 network 192.168.40.240 255.255.255.240
 default-router 192.168.40.254
 dns-server 208.67.222.222 208.67.220.220
 lease 7
!
ip dhcp pool Office-2
 network 192.168.50.128 255.255.255.128
 default-router 192.168.50.254
 dns-server 208.67.222.222 208.67.220.220
 lease 7
!

interface GigabitEthernet0/1
 description Office-1
 ip address 192.168.40.254 255.255.255.240
 ip nat inside
 ip virtual-reassembly in
 duplex auto
 speed auto
!
interface GigabitEthernet0/2
 description Office-2
 ip address 192.168.50.254 255.255.255.128
 ip nat inside
 ip nat enable
 ip virtual-reassembly in
 duplex auto
 speed auto
!



2911(dhcp-config)#do show ip dhcp pool Office-2

Pool Office-2 :
 Utilization mark (high/low)    : 100 / 0
 Subnet size (first/next)       : 0 / 0
 Total addresses                : 126
 Leased addresses               : 0
 Pending event                  : none
 1 subnet is currently in the pool :
 Current index        IP address range                    Leased addresses
 192.168.50.129       192.168.50.129   - 192.168.50.254    0

2911(config)#do show ip dhcp pool Office-1

Pool Office-1 :
 Utilization mark (high/low)    : 100 / 0
 Subnet size (first/next)       : 0 / 0
 Total addresses                : 14
 Leased addresses               : 1
 Pending event                  : none
 1 subnet is currently in the pool :
 Current index        IP address range                    Leased addresses
 192.168.40.242       192.168.40.241   - 192.168.40.254    1
		
		

dns-server 208.67.222.222
dns-server 208.67.220.220
			

dns-server 8.8.8.8
dns-server 4.4.4.4