Installing and Administering Internet Services

200 Chapter 6

DHCP

Conﬁguration Overview

DHCP allows you to exclude certain addresses within a group if you wish

to make them unavailable for assignment. You also have the capability to

deﬁne many values for the devices of a group including address lease

times, DNS servers, NIS servers, and many other optional parameters.

For detailed conﬁguration information, refer to the on-line help that is

provided with the DHCP graphical user interface.

Fixed-Address Devices

In addition to having addresses assigned from groups, DHCP allows IP

addresses to be individually conﬁgured for devices. For administrative or

security reasons, you may want certain devices to have ﬁxed addresses.

Figure 6-2 DHCP Devices Can Have Fixed IP Addresses

Through SAM, you must conﬁgure each ﬁxed-address device with

information about the device, including its own IP address. In the

drawing, assume that you have conﬁgured a DHCP group to include

Client1 and Client2, meaning that each will receive an IP address from a

pool of available addresses at boot request. However, suppose that you

have conﬁgured Client3 and Client4 to have ﬁxed IP addresses. Client3

and Client4, therefore, will be assigned the addresses you conﬁgured for

them upon boot request. Client3 and Client4 will always be assigned

these same addresses unless you change the conﬁguration.

DHCP also allows you to deﬁne many optional parameter values for

clients with ﬁxed addresses.

For more detailed conﬁguration information, refer to the on-line help

that is provided with the DHCP graphical user interface.

DHCP

Client1

Client2

Client3

Server

DHCP

Client4

DHCP

Group A

Fixed