A number of Windows XP users on VLAN_D support DHCP and the ability to receive more than one IP gateway. Configure R2 to provide only a pool of DHCP addresses with the following criteria:
■ The IP addresses pool ranges from 22.214.171.124/26 shared between R2 and R3.
■ The DNS servers are 126.96.36.199 and 188.8.131.52.
■ Default gateway of 184.108.40.206 or 220.127.116.11 only.
■ Hosts must retain DHCP-assigned addresses forever.
■ The predefined addresses 18.104.22.168, 22.214.171.124, and 126.96.36.199 are never allocated to DHCP clients.
You can assume that you have Windows XP clients only and support more than one gateway if any one router fails.
VLAN_D contains the subnet 188.8.131.52/26 with the allocated IP addresses, one each to R2 E0/0, R3 Fast0/0, and the Catalyst 3550 management interface. You must ensure that any DHCP servers (R2, in this case) do not allocate these three preassigned address.
Example 8-63 configures R2 for DHCP pool allocation.
Example 8-63 DHCP Configuration on R2
ip dhcp excluded-address 184.108.40.206 ip dhcp excluded-address 220.127.116.11 ip dhcp excluded-address 18.104.22.168 !
ip dhcp pool ccie network 22.214.171.124 255.255.255.192
domain-name cisco.com dns-server 126.96.36.199 188.8.131.52
default-router 184.108.40.206 220.127.116.11 lease infinite
R2 provides the DNS domain name and two default gateways. Notice that the lease is enabled to be used forever by DHCP clients with the IOS command lease infinite. If R2 fails, all DHCP clients with existing IP addresses will route through Router R3 with the default gateway 18.104.22.168.
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