Linux System Administration

DHCP

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In the upcoming section “Assigning IPv6 Addresses with radvd” we’ll discuss how to

use dhcpd to hand out static IP addresses based on the MAC address of a client’s net-

work card. But before we do, let’s look at a simple version of /etc/dhcpd.conf:

ddns-update-style interim;

default-lease-time 600;

max-lease-time 7200;

subnet 192.168.1.0 netmask 255.255.255.0 {

option routers 192.168.1.1;

option subnet-mask 255.255.255.0;

option domain-name-servers server.centralsoft.org,

server2.centralsoft.org;

range 192.168.1.2 192.168.1.254;

}

For simple DHCP servers, maintenance may actually be easier if you

omit comments and keep the configuration file short.

Starting Your DHCP Service

Some DHCP services require a dhcpd.leases file. Use the touch command to create an

empty file in the same directory as the dhcpd.conf file:

# touch /var/lib/dhcp/dhcpd.leases

You’ll want to start your DHCP server now, to check whether the configuration is

correct. You’ll also want to configure the server to start on boot. To accomplish the

first task, enter:

[root@host2 ~]# service dhcpd start

Starting dhcpd: [ OK ]

[root@host2 ~]#

You can also test whether the DHCP process is running with the following com-

mand (if the service is running, a line will be displayed with the process’s statistics):

# ps aux | grep dhcpd

root 9028 0.0 0.0 2552 636 Ss 09:40 0:00 /usr/sbin/dhcpd

Use the chkconfig command to get DHCP to start at ...