This means that the ISP is essentially using a router on their end to use less internet addresses.
Let's save everyone time here. It's not going to work out. http://forum.whatismyip.com/f5/private-ip-assigned-by-isp-wth-t875/ and more covers this.
VPN? Try it. May be the only exit here.
I got PlayStation 4 last time and I have a problem - I have a router TP-LINK TL-WR542G (no DD-WRT) and I plugged Ethernet cable into the PS4. Everything is working fine, download and upload speed is average (faster than Wi-Fi), but there's one major problem here. And that's NAT TYPE 3 - STRICT. I Googled literally for hours, tried EVERY solution possible (Port Forwarding, DMZ, UPnP, Wi-Fi and wired connect,... everything!) and I still can't get rid of it. Even on PC in every game I have Strict NAT. I realized that I don't have PUBLIC IP (I've got Private) and some people told me that I can't do anything without public IP. I tried to call my ISP and they said that unfortunately they don't offer public IPs and there's no another ISP in my local area. I am REALLY frustrated, because voice chat, Share Play, online games etc. don't work properly and I want to play with my friends.
I've read some articles and I know about VPN connections. Not that it's secured and nobody can see what am I doing, but I will get even Public IP (as one of the personnel told me) and MAYBE it might help me with this. Is there ANY other solution? To be honest, I've tried really everything. I am living in Czech Republic and my ISP isn't bad, just doesn't offer this option. Will VPN help me? Is there any way to get rid of this? I've read almost every thread, every article, every solution and saw every video about NAT Types and how to improve it. I spent hours configuring and playing with my router's settings, nothing.
Thanks for help and I hope there's someone who can save me a headache and sleepless nights. See you and I am looking forward to any reasonable answer!