[stacer]

Hi all,

I recently decided to try VoIP service from AT&T and can get everything to work except I can't host games with computers outside my network. I am tired of waiting for hours for their tech support and wondered if someone here might have the answer. My setup is the following:

cable modem -->telephone adapter (appears to be a modified D-Link router)--->

Belkin router--->desktop iMac and airport networked to laptop and additional iMac

I was told that the problem was two tandem NAT devices and to connect the D-Link to the LAN port in the Belkin instead of the WAN. This didn't work. Do I have to make additional settings changes on the Belkin as well? ie turn off NAT? I have the appropriate ports open on the D-link for the game, but do I have to have them open on the Belkin as well if it is connected to the LAN port?

I have only limited networking knowledge and any information is appreciated.

Thanks in advance,

Stacey

[ghporter]

I agree that your problem is two NAT routers in series. A NAT (Network Address Translataion) router hides what's on its LAN side by messing with the ID data in each packet-it Translates the Network Address so that everything coming through it looks like it's from one computer. No biggie when that's the only router. But when you have a second router after that stage of NAT doing the same thing, you have pretty much hidden your LAN from everyone-even people you want to have access.

What you need to do is establish a non-translated path from your cable modem to your computer. Not knowing what sort of D-Link router you have, it's kind of hard to know which direction to send you for this.

If the D-Link has an available LAN-side ethernet port, AND if you can access its setup and configuration pages, you should be able to plug your computer into that port, and set up a "DMZ" for your computer's (fixed) IP address. This exposes the computer to the Internet without any filtering or address translation.

If you can find a model number on the D-Link box, and tell me more about it-like what you can and can't do with it, how many ports it has, etc.-then I can be of more help.

[stacer]

The D-Link is a D-Link VoIP Gateway model no. DVG-1120M. It has one WAN input from the modem and one ethernet out in addition to the phone connections. You can configure the D-Link via web browser, and it looks like you can configure it similarly to any router...WAN/LAN settings, Firewall, ports, etc. Since it acts as the router, I don't really need the Belkin, except that I need two Ethernet out connections...one for the desktop iMac and the other for the airport (old version so no extra ethernet here either). I have considered just buying a hub or switch, but is there some way to change the settings on the Belkin (router behind the D-Link) so that it simply acts as a hub instead of a router/NAT?

Thanks for any tips.

[ghporter]

The simplest thing to do is to move the cable between the D-Link and Belkin boxes from the Belkin's WAN port to a LAN port. This will make the Belkin look like a simple switch to everything on your network, and it won't require changing ANY settings anywhere. Now, all you'll have to do is set up the DMZ to expose your gaming host and you should be all set.

[stacer]

That's what tech support suggested, and I couldn't get it to work. The outside computers couldn't join the game. I'll look again at the D-Link settings for anything that I missed. Thanks for the advice, but maybe VoIP isn't for me. It seems like they should come up with a way that you don't have to redesign your network to get it operational. I'll let you know if I find a solution.