NAT type problem - need help

Hello to the beatifull community of GAMESPOT.

I own a ps3 and im playing online games with it and i have a huge problem with NAT type

Games listed below with NAT's

AC3 AKA Assassin's creed 3/Moderate/strict nat and having bad communication with players (they are teleporting always and i cant play with couple of friends)

RDR AKA Red Dead Redemption/Strict NAT i cant join a lot of friends and it throws me everytime when i go to a free roam session and heavy lag nat fault.

So how do i fix this? i have not tried anythin at all just a wireless connection from my router to my ps3 100% signal

Ps3 options all automatically connected to my router

My router's manufacturer and ID D-link DSL-2680 

My router's statistics 

The router is updated to the newest firmware out there so what i do?

If i enable DMZ what are the benefits will i get OPEN-NAT on all games/psn?

Port forwarding what will it help?

What is the best way to get OPEN-NAT in all games? Also forgot to mention that in my router it has a built in firewall that is enabled at default

Cheers

Its been a while since i seen or had this problem, hence i dont remember exactly how. What i do remember is you are having a Firewall issue, try disabling the firewall from your router to free up the connection to your PS3, i am sure you can find Youtube videos of how to disable firewalls on your router or wireless service. Goodluck

So if i disable my firewall on my router isnt that insecure?