The Dhcp Server Dhcpd - Novell LINUX ENTERPRISE SERVER 10 - INSTALLATION AND ADMINISTRATION 08-05-2008 Installation Manual

34.3 The DHCP Server dhcpd

The core of any DHCP system is the dynamic host configuration protocol daemon. This
server leases addresses and watches how they are used, according to the settings defined
in the configuration file /etc/dhcpd.conf. By changing the parameters and values
in this file, a system administrator can influence the program's behavior in numerous
ways. Look at the basic sample /etc/dhcpd.conf file in
Configuration File /etc/dhcpd.conf"
Example 34.1 The Configuration File /etc/dhcpd.conf
default-lease-time 600;
max-lease-time 7200;
option domain-name "cosmos.all";
option domain-name-servers 192.168.1.1, 192.168.1.2;
option broadcast-address 192.168.1.255;
option routers 192.168.1.254;
option subnet-mask 255.255.255.0;
subnet 192.168.1.0 netmask 255.255.255.0
{
range 192.168.1.10 192.168.1.20;
range 192.168.1.100 192.168.1.200;
}
This simple configuration file should be sufficient to get the DHCP server to assign IP
addresses in the network. Make sure that a semicolon is inserted at the end of each line,
because otherwise dhcpd is not started.
The sample file can be divided into three sections. The first one defines how many
seconds an IP address is leased to a requesting client by default
(default-lease-time) before it should apply for renewal. The section also includes
a statement of the maximum period for which a machine may keep an IP address assigned
by the DHCP server without applying for renewal (max-lease-time).
In the second part, some basic network parameters are defined on a global level:
• The line option domain-name defines the default domain of your network.
• With the entry option domain-name-servers, specify up to three values
for the DNS servers used to resolve IP addresses into hostnames and vice versa.
Ideally, configure a name server on your machine or somewhere else in your network
650 Installation and Administration
(page 650).
# 10 minutes
# 2 hours
Example 34.1, "The