Relevant link: http://www.linuxhomenetworking.com/w...he_DHCP_Server
I recommend adding the below text, as I've used this successfully numerous times on Red Hat based systems:
The DHCP daemon can be configured with command line options in the /etc/sysconfig/dhcpd file. For example DHCP can be bound to a single network interface.
[bash]# vi /etc/sysconfig/dhcpd
Set the following argument to provides queries/assignment on the indicated network interface.
# Command line options here