Do not configure a new DHCP server on a network that is already serviced by another DHCP server. This can cause conflicts and result in PXE Boot failure.

If you have not already installed a DHCP server, you can do so by doing:

# yum install dhcp

Set up your DHCP configuration file (/etc/dhcpd.conf) so that only PXEClient requests receive PXEClient responses. Add the following entry to the DHCP configuration file (refer to the dhcpd.conf man page for more information):

class "PXE" {
    match if substring(option vendor-class-identifier, 0, 9) ="PXEClient"; 
    option vendor-class-identifier "PXEClient"; 
    vendor-option-space PXE; 
    next-server n.n.n.n;
    filename = "pxelinux.0";
}

where n.n.n.n is the IP address of the DHCP/PXE server.

In the DHCP configuration file, also edit the server-identifier entry:

server-identifier    n.n.n.n;

where n.n.n.n is the IP address of the DHCP/PXE server.

Also in the DHCP configuration file, find the following subnet entry fields:

subnet 1.2.3.0 netmask 255.255.255.0 {
range dynamic-bootp 1.2.3.100 1.2.3.200;
option routers 1.2.3.1;
option broadcast-address 1.2.3.225;
}

Edit the subnet, range, router and broadcast-address entries according to the DHCP/PXE server's network configuration.

Start the DHCP service:

# service dhcpd start

Finally, configure the DHCP to always start at boot:

# chkconfig dhcpd on