21 DHCP CONFIGURATION GUIDE
DHCP Server Global
Address Pool
Configuration Guide
In general, there are two typical DHCP network topologies. One is to deploy the
DHCP server and DHCP clients in the same network segment. This enables the
clients to communicate with the server directly. The other is to deploy the DHCP
server and DHCP clients in different network segments. In this case, IP address
assignment is carried out through a DHCP relay agent. Note that the DHCP server
configuration is the same in both scenarios.
Network Diagram Figure53 Network diagram for DHCP server global address pool configuration
Networking and
Configuration
Requirements
■The DHCP server (Switch A) assigns IP addresses to clients in subnet
10.1.1.0/24, which is subnetted into 10.1.1.0/25 and 10.1.1.128/25.
■The IP addresses of VLAN-interface 1 and VLAN-interface 2 on Switch A are
10.1.1.1/25 and 10.1.1.129/25 respectively.
■In the address pool 10.1.1.0/25, the address lease duration is ten days and
twelve hours, the domain name suffix is aabbcc.com, the DNS server address is
10.1.1.2, the WINS server address is 10.1.1.4, and the gateway address is
10.1.1.126.
■In the address pool 10.1.1.128/25, the address lease duration is five days, the
domain name suffix is aabbcc.com, the DNS server address is 10.1.1.2, and the
gateway address is 10.1.1.254; there is no WINS server address.
■Enable unauthorized DHCP server detection on Switch A so that the
administrator can check out any unauthorized DHCP servers from the system
log information.
WINS server
10.1.1.4/25
Client
Switch B
Client
DNS server
10.1.1.2/25
Switch A
DHCP server
Vlan-int2
10.1.1.129/25
Vlan-int1
10.1.1 .1/ 25
Client Client
Client Client
Vlan-int1
10.1.1.126/25
Gateway A
10.1 .1. 254 /2 5
Gateway B