Multi-Homed Networking in Linux (CENTOS 5.4)

[gasbie]

Guys, please help me out. I'm really stuck on this project.
I'm trying to set up a multi-homed network. Click on the jpeg below to see
my setup diagram. Is that right. I'm using a 8 port netgear switch. port 1-3
is for vlan 100 and port 4-6 is for vlan200. port 7 is for management and port
8 is for printer. Both port 7 and port 8 are members of vlan 1. As you can see,
I have connected each vlan (vlan 100 and vlan 200) to the router so that computers
on these vlan can communicate with each other. But my main problem are as follows:

How do I define the dhcpd.conf scope to include all these networks?
How do I configure the dhcp server to distribute ip address to various networks?
Does eth0 has to be member of the vlan 100 or vlan200 or can I just connect the eth0
cable to vlan1, which is the default?
I created eth0.100 and eth0.200 on interface eth0. Which network should the physical eth0
be in? Do I have to define a network and netmask for the physical eth0 or leave it as default
since it has many other vlan on it?
How can I reroute stuff in and out of these networks?

Please if you have done this setup before, I will appreciate if someone can tutor me through
this project. Thanks

[topdog]

create vlan interfaces for all the vlans you are going to dish out dhcp addresses to on the server, then use pools to assign the dhcp parameters per vlan. look at

man dhcpd.conf

for details

for the vlans to talk to each other you need to enable ip forwarding on the linux box, you may want to use iptables as well to restrict who talks to who.

if vlan1 is a native vlan then you can just connect the cable as the switch will allow transmission of untagged frames for this vlan.

You really do not have to do any routing as the default gateway for each vlan will be an interface on the linux machine which is directly connected to the other vlan's and has a route for each in its routing table.