Install the dhcpd rpm, make a subnet definition, and change /etc/init.d/dhcpd to only operate on your lan interface..
Rpm from
dhcp-2.0pl5-8.i386.rpm
or any other mirror for redhat.
If you're lucky, you can still use
up2date to install it
or from your install cds, cd 2
The online guide is at
http://www.redhat.com/docs/manuals/l...e/ch-dhcp.html