My PS3 has a NAT type of 3, which resrticts communication online. I have a Siemens Speedstream 6520 modem/router, and I've tried everything to get my PS3 to NAT 2. I've DMZed it and forwarded the ports, but no luck. Am I missing something?

Hi, did you try this yet?
Port Forwarding for the Siemens Speedstream-6520

yep, still doesn't work

Here is what the PS3 forum is saying...

Watch the video...


Hope this helps..

LC

Well, I tried every combination of UPnP on/off and DMZ on/off and still no luck. You'd think when I DMZ the PS3 everything would be fine, maybe it's just an error on the PS3's side..

I'm having a similar problem with my Speedstream 4200. I couldn't get port forwarding or DMZ to work for me either. What I found is that if I went into the NAT settings and enabled NAT for the PS3s IP, I was able to get to NAT Type 2. However, this also causes me to lose my internet connection to my computer. I'm still trying to figure out how to fix this. I don't know if this will work in your situation but its something that was at least able to get me a bit closer. Also, if you have a secondary router (like a wireless router) in between your modem and your PS3, theres additional steps you have to take there. I had to find that out the hard way.