Dynamically assigning Client IP Addresses via DHCP on Cisco Router
DHCP assigns IP addresses and
other important network configuration information to clients dynamically. Cisco
router uses the Cisco IOS feature known as Easy IP as an optional DHCP server.
Easy IP leases IP configurations to network clients for 24 hours by default. we
use the topology diagram below as sample network topology.
Step 1.Configure excluded
address(es): These addresses are reserved for network hosts or clients that
need static addresses, such as servers, routers and printers. These IP
addresses are not included in the address pools that are available for
assigning to other clients.
DHCP excluded address
on R1:
R1#config terminal
R1(config)#ip dhcp excluded-address 192.168.30.1
192.168.30.9
R1(config)#end
R1#
Step 2. Configure the address pool: Define the pool of addresses from which DHCP assigns addresses to clients on the network. in this case (R1) the available addresses are all addresses on the 192.168.30.0 network, except for the range excluded on
step 1.
Configure address
pool on R1: define the address pool, default gateway, and DNS server that are assigned to each client requesting for DHCP IP configuration.
R1(config)#ip dhcp pool R1LAN
R1(dhcp-config)#network 192.168.30.0 255.255.255.0
R1(dhcp-config)#default-router 192.168.30.1
R1(dhcp-config)#dns-server 192.168.10.254
R1(dhcp-config)#end
R1#
Do the same on R3 in this case:
Excluded address for
R3:
R3(config)#ip dhcp excluded-address 192.168.20.1
192.168.20.9
R3(config)#end
R3#
Address pool for
R3:
R3(config)#ip dhcp pool R3LAN
R3(dhcp-config)#network 192.168.20.0 255.255.255.0
R3(dhcp-config)#default-router 192.168.20.1
R3(dhcp-config)#dns-server 192.168.10.254
R3(dhcp-config)#end
R3#
