I must be missing something blantantly obvious...

[Mr. Chambers]

I must be missing something here fellas, I have a friends network setup like this:

cable modem --> linksys wrtgl (with DD-WRT) --> computer

I have the WinXP firewall disabled, the ports I want forwarded set to forward both UDP/TCP to the computers IP, and I have the cable modem set up to DMZ to the linksys router IP address. The ports still aren't forwarding! Am I just having a terrible brainfart here?

[Know Nuttin]

you shouldn't need to set the cable modem to DMZ. All you should need to do is set the internal IP's to the proper forwarded port.

[Mr. Chambers]

I know I shouldn't need to, but somethings up so I figured that would rule out a mistake in the port forwarding...

I narrowed it down a bit more, I plugged his other PC straight into the modem (gateway), and forwarded a different set of ports to that PC's IP and those ports show as open.

[Know Nuttin]

I'm getting a bit confused.
So you bypassed the router and went direct to the modem and still forwarded ports on what?

[Mr. Chambers]

I'm getting a bit confused.
So you bypassed the router and went direct to the modem and still forwarded ports on what?

His "modem" is a gateway - it has a built in firewall as well. It's a Netgear Wireless Gateway. I saw where to turn off the wireless functionality (he wants to use the DD-WRT obviously) - but can't see where to turn off the firewall function (other than DMZ'ing it to his router IP and letting the router do the firewall duties?) Clear as mud?

[Know Nuttin]

I'm thinking perhaps the DMZ'ing to the router might not be working?