The latest and greatest installment in the Call of Duty franchise just went live yesterday on XBOX 360, PlayStation 3, and PC. One issue that comes up every time a new CoD game is released is the NAT type issues. The game lists three different NAT types when you’re in the multiplayer section, they are Strict, Moderate, or Open.

Strict is a pretty severe issue for most, and that means your traffic really isn’t getting through to the game and you’ll likely have issues joining and hosting games if you can even play at all.

Moderate isn’t something to be hugely worried about unless you notice issues getting into the games. Most likely moderate would keep you from hosting games yourself though and should be fixed.

Open is where you want to be, all traffic between the game and the host/server is free flowing.

On XBOX 360 and PlayStation 3, you should just set a static IP address to your console and put it in the DMZ (De-Militarized Zone) on your router. The DMZ is a big security risk for a PC, but it’s nothing to be worried about the consoles.

If you’re like me, and on a PC and have a NAT type of Moderate it will drive you insane until it is fixed…

The quickest way to solve this, is to be sure UPnP and NAT-PMP are ENABLED on your router. Look around in the settings as each router is different, but be sure to enable them, or check the boxes next to those options. If you were at Strict before this should get you to Moderate, but there’s one more step to get from Moderate to Open, and that is actually a simple solution.

Open up Windows Firewall with Advanced Security and create new Inbound and Outbound rules for “iw5mp.exe” (Located in Steam\steamapps\common\call of duty modern warfare 3\) and be sure to explicitly allow all connection both inbound and outbound.

The default location for iw5mp.exe is as follows…

C:\Program Files\Steam\steamapps\common\call of duty modern warfare 3\iw5mp.exe

If you’re on a x64 system, it will be similar, just inside the Program Files (x86) folder instead.

Restart your PC for good measure and fire up the game one more time and verify your NAT type is now Open.


18 Responses to “[GUIDE] Get NAT Type: Open in Modern Warfare 3”

  1. Gerlof says:

    Thank you!!
    Now my nat type is open but not for Coop.
    Do you have a solution for that?


    Corey DeGrandchamp Reply:

    @Gerlof, That’s strange, if it fixes it in one place it should fix it in the other. Try adding iw5sp.exe to the firewall as well, coop might be running through that .exe instead of the mp for the multiplayer .exe


  2. Eldaner says:

    nope, not for coop. I can play multi, but not coop. NAT :(((


    Corey Reply:

    @Eldaner, Did you add the IW5SP.exe to the firewall as well? It worked for me.


  3. jorricks says:

    Nope co-op will not work!
    And you can say it will.. But even with
    - the firewall on my pc out
    - the ports forwarded on my router
    - upnp on with Advertisement Period = 5 and Advertisement Time to Live = 50
    I still have moderate so..


    Corey Reply:

    @jorricks, Use some packet sniffers to find what ports aren’t being allowed though then? I’m not sure what else to say?


  4. diri says:

    hey mine is still moderate T_T


  5. karabouzouklis says:

    mine is still moderate too


  6. Jack says:

    Mine hasnt worked still at strict I tryed going in router and tried everything you said nothing it angers me can you help? I’m running Windows XP


  7. parrafin23 says:

    Funny this NAT thing.. I have no router or firewall what so ever, worked fine before the release of dlc package 1

    Now with the dlc package released i now have moderate NAT.. Wtf?


  8. metoo says:

    yes, it was DLC 1 update that changed mine to moderate…so sucks bad because its so hard to find a match with moderate


  9. Hamish says:

    What did you mean by Static IP? Sorry im not big on computers and all that. How do i set up a Static IP? I have wireless and the original white 360.



  10. PePeeK says:

    Hi pls i make this and i have Nat only Moderate


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  12. MadDogg says:

    It didnt work for me someone help me ive gone nearly 130 day without multiplayer


  13. tom says:

    I dont have the file “iw5mp.exe Its only showing 1 file iw5 but its not a .exe


  14. ALIE says:



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