Hi guys I don't know what I can else do. My old firewall (Fortigate) get broken. Unfortunatley the NAT isn't working with my new one (Checkpoint) anymore.Maybe you guys have some ideas. First of all, it is a real firewall (like my old one), not a home router. So I don't have UPnP and such things. On the old one I have forwarded (static NAT) the needed ports to the PS4. I've got NAT Type 2. On my new one I do the same, with the same ports. I only get NAT Type 3. If I analyze the traffic on the firewall with the sniffer, I see the firewall is translate the traffic from the external interface to the PS4. All looks good, but I still get NAT 2. There are also only a 2-4 packet drops, if I run the test. But I'm sure that's not the problem. I wasn't able to test voice chat yesterday. I'll also try to connect the PS4 directly to the internet, to see if I get NAT 1. Maybe my ISP has changed something, but I don't think so. That would be a huge coincidence... So I'm completly out of ideas... EDIT: I forgot to mention. It's not only Destiny told me I have NAT 3, it's the test on the PS4 itself. I'm not sure, but I think Destiny is taking only the information from the PS4 and not making an own NAT test. Thanks!
Ok the problem is solved for me. Why? I don't know. How? Maybe an idea... I had contact with Playstation support, about the NAT problem. They told me I shall set the MTU to 1473 for LAN (or MTU 1476 for WiFi) on the PS4. I tried, but it didn't work. Waiting to answer, I changed the connection type from Lan to Wifi. Changed the IP on the firewall for the NAT, run the test -> NAT Type 2. Ok, the same way back to Lan, running the test -> NAT Type 2 I don't know why it's working now, but I suppose changing the connection type on the PS4 resets the local firewall or network stack (or something else). I asked Playstation support about this possibility. If I get an useful answer, i'll post it here. Maybe it helps someone to solve a NAT problem as well.