Sup man. First, if you're wondering what a DMZ is, this stands for a demilitarised zone. It really means that rather than opening just one port on your routers firewall you are actually opening every single one. Port opening is another simple process, however it takes a bit of time to find exactly what ports need opening, and sometimes, the ports listed may not solve the problem you have. Putting your PS3 into a DMZ is not a bad thing, and is much easier than opening port for the reason listed above. Now you may need to do this for some of the following reasons:
Not being able to join rooms
Not being able to speak over headset
Not being able to hear over headset
Not being able to join games which are hosted by certain people
Any problems to do with connectivity to the PSN or game specific servers, especially if your computer will connect to the internet, but PS3 won't.
Now on with the guide:
To put your PS3 into a DMZ
1) Firstly, you will need to assign your PS3 a static internal Ip address. This means that everytime your PS3 connects or "talks" to your router, the router will assign it a different internal IP address. These IP addresses typically run in series. So for example, if your PS3 is the second device communicating with your router, then it will be assigned an ip address of 192.168.1.3. However, if you choose to use your PS3 without the computer being on, the assigned IP address your PS3 has will be 192.168.1.2. As this is different, and obviously will change, it would be stupid setting a DMZ up on one of the above Ip addresses, unless your PS3 was the only device that would ALWAYS connect using that specific IP.
To make sure that your PS3 is always assigned the same internal IP address by your router, you will need to go to the "Settings > Network Settings > Internet Connection Settings" option on the PS3 Cross bar menus.
You will be presented with an option which primarily asks whether you are using a Wired or Wireless connection. Obviously, you will choose the option which refers to you. If choosing the Wireless option you will need to input the security details in use on your router *If you are not currently using wireless security, i strongly recommend you do so ASAP*
Both selections should show a page called "Address Settings". Here you will need to select "Custom". Another page will then display entitled "IP Address Setting". The option "Manual" will need to be selected. This will display a page where customisable IP Addresses are available to be selected. IP Address - This will need to have the Static IP address in it. Personally, i use 192.168.1.100. I use this because it is extremely unlikely my Router will ever automatically assign this IP Address to a device, as i will never have 99 other devices connected to the same system.
Subnet Mask - Is always set to 255.255.255.0 Default Router - Is the internal IP Address of your router. To get the exact ip of your router you should go to Start Run cmd Type in ipconfig and hit enter, this should come up with all the ip addresses to do with your computer and the network. The address you will need to enter in this option is listed as "Default Gateway". Primary DNS - Same IP Address as "Default Router" Secondary DNS - Same IP Address as "Default Router" After entering all of these IP Addresses, you will now click "Enter" or hit the "right" button on the D-Pad. This will take you to a screen which says "MTU" at the top. My setup has this as Automatic, solely because i haven't a clue what MTU actually means or does.This won't affect your ability to set up a DMZ.
The next steps are very simple. You do not want to use a proxy server unless you connect to the internet using one, however i can be of no help there, and you should enable UPnP if your router supports it.
2) Now head over to your PC, and load up your internet browser. In the Address Bar, type the IP Address of your router (the one you found using the Command Prompt earlier) This will take you to your Router Configuration Page. Every router interface differs from an other, and depending on what router firmware update you last installed, router interfaces can differ, even on the same model routers. This means that you will need to search the router config page yourself.
You are looking for any mention of "DMZ" or "DMZ Host" When you have found this, it will ask you generally to input the IP Address of your DMZ Host, which is just the static IP address you assigned to your PS3 earlier, my example was 192.168.1.100, so we'll stick with that.
Then click "apply" or similar. You should then turn off everything running on your home network. PS3, PC, Router etc. This is solely to make sure that the changes are applied as soon as possible. This should fix all of the problems as listed earlier in this guide, and probably some other issues which I, myself have not encountered yet.
BTW this guide isn't completely mine but i hope it helped.
As for the game update part, try using awesome update finder to download updates and install them manually