Can I use my WRT54G as a DHCP server only? I've got 5 dynamic IP's from Time Warner..

Question

Hi everyone, I'm wondering if I can use my WRT54G as a DHCP server only only my network, without having to have any of my PC's plugged into it's router ports?  I looked at the settings but I couldn't get it to work.
Here's why:  I just got Time Warner Business Class cable internet which comes with 5 dynamic IP's.  I want each computer, well 4 of them at least and 1 for the WRT54G, to have a unique IP when accessing the internet, and the other computers (5 more computers) to use the DHCP server in the WRT54G to get a NAT IP for use on the internet.
We play Diablo II on the internet and only 4 computers can be connected through 1 IP, so that limits us in my current configuration.
Current Equipment: One WRT54G, one Netgear GS116 16 port gigabit non-managed switch.  One Time Warner Cable modem.  Also attached to the network is one HP network printer, a Buffalo LinkStation NAS and a Zensonic Network DVD player.
Current config:  Cable modem -->  WRT54G --> Netgear switch.
Ideal config: Cable modem -->  Netgear switch -->  WRT54G.
With my current config, I am not taking advantage of the 5 dynamic IP's, but all the computers connected to the Netgear switch or the WRT54G can connect to the internet and the NAS. 
So my ideal config (where I don't have to buy anything and where all the computers can print and access the NAS) is to connect all the computers and devices to the Netgear Switch and somehow force 4 of the computers and the WRT54G to get a dynamic IP from the cable modem, while the other computers and devices use the DHCP server on the WRT54G to get to the internet. 
Is this possible?
I called Time Warner Cable and they weren't any help.  I called the Linksys sales department and they weren't of much help either. 
I suppose that I could purchase a new 8 port switch and attach 4 computers, the cable modem and the WRT54G to it.  Then attach the Netgear to the WRT54G to accomodate the printer, NAS, and the other 5 computers.  But in that senario, the 4  computers connected to the new switch can't print and can't reach the NAS.  And geez, some computers would have to go through 3 devices to reach the internet, which has got to slow them down.
I did read about the Linksys EFG120 which has a DHCP server, but at $400 and only 120 gigs, it doesn't work for me. 
I called Time Warner and the cost of more dynamic IP's is prohibitive, I'm already paying $79 a month for this internet and they want another $50 a month for 7 more dynamic IP's and that wouldn't help my NAS or my printer.
The cost of a 16 port gigabit switch with DHCP is an amazing $800 or so, which is out of the question. 
Sorry for being so long winded and thanks for reading this far.  I'm looking forward to any replies. 

Answer 1

That is a hell of a setup. I don't know if it would be easier and cheaper to either buy a real router like a Cisco, get fixed IP addresses and a RV042, or buy 4 network cards for the four of the five computers which need the internet access for gaming.
O.K. First your setup:
1. You wire the modem to the 6-port switch.
2. You connect the remaining 5 ports with the WAN ports of 5 WRTs with DHCP on the WAN interface.
3. You configure each WRT with unique LAN IP addresses in the same subnet, e.g. 192.168.1.1/255.255.255.0, 192.168.1.2, 192.168.1.3, 192.168.1.4, 192.168.1.5.
4. You turn off all DHCP servers except on one, e.g. 192.168.1.1. That router will be the default router and internet connection for any client which gets dynamic LAN addresses (as fallback or guests, I would not configure the NAS or printer with DHCP addresses if you have everything else on static IP addresses). You can certainly disable all DHCP servers if you want, too.
5. Now you connect all WRTs with each other.
5a. You connect port 1 of the 1st WRT with port 1 of the 2nd.
You connect port 2 of the 2nd with port 1 of the 3rd.
Port 2 of the 3rd with port 1 of the 4th.
Port 2 of the 4th with port 1 of the 5th.
(Do not create a loop connecting port 2 of the 5th with port 2 of the 1st!!)
5b. You buy another switch and connect each port 1 of each router with this switch. This has the advantage that you don't have a long cascade between the 1st and the 5th router like in 5a.
6. You connect all devices to the LAN.
6a. If you did 5a, you will probably put each computer to the router which internet connection it uses. The NAS and printer could go anywhere.
6b. If you did 5b, you hopefully bought a 16 or 24 port switch. Then you plug simply everything into that switch. Otherwise you can certainly use the free ports of the WRTs like in 6a.
7. You configure all your devices with static IP addresses. For instance,
IP 192.168.1.11
netmask 255.255.255.0
gateway 192.168.1.1
For the DNS servers I would highly recommend to use the DNS servers of your ISP directly and not use the relay on 192.168.1.1.
The gateway address defines through which router the computer connects to the internet.
8. You may still have to configure port forwardings on the router to the game computer if required for the game.
An interesting alternative to this setup might be to buy 4/5 network cards for the 4/5 computers with direct internet access. Then you use the one network card to connect to your single LAN behind your single WRT. The other network card goes into the switch behind the modem and has direct internet access. You then have to tell Windows which of the network cards has the default gateway for the internet connection (to prevent routing all traffic through the LAN and the WRT to the internet). One game computer would have to be behind the WRT.