Help w/ multiple NAT routers

I’m trying to set up my home network connection, with the computers behind three NAT swtich/routers. Why three you ask? The first in line is my Motorola VT1000v, which is a VoIP box used with my Vonage phone service. It has a WAN connection that goes to my cable modem, but only one LAN connection. So downstream from it I have a Belkin switch/router with four LAN ports, plus 802.11b. I have one computer connected to the cabled LAN port, and I have a notebook that I connect via WLAN.

This works fine, with one exception. Sometimes I need to transfer large amounts of data between my notebook and my desktop PC, so I connect the cabled LAN interface to my notebook PC (since it’s faster than WLAN). But this Belkin p.o.s. (which I bought for $15) has a dismal transfer rate of only about 1 Mbps between two cabled ports. Transfers take hours.

So my great idea is to take my Microsoft switch/router, which I used before I got WLAN, and put it downstream of the Belkin router, and use the 10/100 ports on it for the cabled connections. When my notebook is operating wireless, I can connect to the Belkin, then when I need to transfer data, I plug in the cable and data goes quickly across the Microsoft router without ever passing through the Belkin.

So it’s like this:

Cable Modem
|
Motorola VT1000v - uses NAT, downstream address 192.168.102.1.
|
Belkin WLAN router - uses NAT, downstream address 192.168.2.1.
|
Microsoft 10/100 router - uses NAT, downstream address 192.168.3.1
|
Two 10/100 connected PCs.

The problem with this configuration is that with the two wired PCs, DNS apparently doesn’t work (surfing to a host name doesn’t work, but entering that host’s IP address directly does work). The subnet masks in each case are 255.255.255.0, and the default gateways are all the respective upstream router. This appears correct to the limits of my knowledge of NAT - can anyone shed more light on it?

Also, the same problem happens if I put the Belkin downstream of the Microsoft router - then the DNS failure is on the Belkin-connected PCs. It all seems to work with two NAT routers, but adding the third breaks it.

Why do you want NAT running on the Belkin & MS routers? You should disable NAT on those boxes and use them simply as switches. Also, disable DHCP for those boxes, as well, and have it running on the Motorola, only. Double-check to make sure you don’t need a crossover cable for the uplink ports.

Just change the modes on the two downstream ‘routers’ so that they function as switches instead. You won’t have to NAT through those, and you’re still behind the router that sends your cable modem and VoIP to the Internet.

Also, you don’t want them handing out DHCP addresses. What is good is to give each one of those a static private address, and allow your VoIP router to hand out DHCP to the rest, or if it’s a really small net, you can give all your devices static private addresses and not have them dynamically assigned at all.

There is no reason to do multiple layers of NAT in your situation.

Hodge is right about the uplink ports. If these swtiches do not have a specific port for uplink, you will very likely need a crossover cable to connect switch to switch.