3Com 10014299 manual III. Configuration Procedures 1 Enable the Dhcp service, Router dhcp enable

DHCP Server Configuration 343

Typical DHCP Server The common DHCP networking methods can be classified into two categories: Configuration Example One is that the DHCP server and the clients reside on the same subnetwork and

they directly carry out the interaction of DHCP. Another one is that the DHCP server and the clients reside on different subnetworks and they must implement the allocation of IP addresses through the DHCP relay proxy. In both these cases, the DHCP configurations are the same.

I. Networking Requirements

DHCP server allocates IP addresses dynamically for the clients in the same segment, the address pool segment 10.1.1.0 is divided into two segments:

10.1.1.0(the mask is 255.255.255.128) and 10.1.1.128 (the mask is 255.255.255.128). The two Ethernet interfaces of the DHCP server are 10.1.1.1 (the mask is 255.255.255.128) and 10.1.1.129 (the mask is 255.255.255.128) respectively.

In the segment 10.1.1.0, the address lease period is 10 days and 12 hours, the domain name is 3com.com. The DNS address is 10.1.1.2, without NetBIOS address, and the outgoing router address is 10.1.1.126. In the segment 10.1.1.128, the address lease period is 5 days, the DNS address is 10.1.1.2, the NetBIOS address is 10.1.1.4, and the outgoing router address is 10.1.1.254.

II. Networking Diagram

Figure 126 DHCP server and clients reside in the same network

NetBIOS	Client	Client
Serv er			Client

Outgoing router A

Router

LAN

DHCP Serv er

Router

Outgoing router B

LAN Router

DNS Serv er Client Client Client

III.Configuration Procedures 1 Enable the DHCP service.

[Router] dhcp enable

2Configure the IP addresses (DNS address, NetBIOS address and outgoing gateway address) that do not participate in auto-allocation.

[Router] dhcp server forbidden-ip 10.1.1.2

[Router] dhcp server forbidden-ip 10.1.1.4

[Router] dhcp server forbidden-ip 10.1.1.254

3Configure the common attributes (pool address range, domain name, DNS address) of DHCP address 0.

[Router] dhcp server ip-pool 0

[Router-dhcp0]network 10.1.1.0 mask 255.255.255.0

[Router-dhcp0]domain-name 3com.com

[Router-dhcp0]dns-list 10.1.1.2