Watch the video:

0:00 - Intro/Explanation
0:25 - Allow MW3 through Windows Firewall
1:01 - Port Forwarding
3:38 - Open NAT in MW3
3:50 - Alternatively, try UPnP

While opening your NAT type in Call of Duty: Modern Warfare 3 is not required for a smooth gameplay experience, some users believe there is a huge benefit to doing so. Heck, you have likely done it before if friends struggle to join you, or you them. This is the only place I’ve noticed it before: Hosting lobbies. This guide shows you how to open your NAT type, and if you’re confused - there’s a video to go along with it.

If you’ve ever port forwarded or opened your NAT for Warzone, then you likely already have a NAT type. Make sure to check it first.

This guide also includes ports for Playstation and Xbox, so you can follow along - Just use the device’s local IP address, and skip the Windows Firewall step - obviously.

The easy way

If your router supports UPnP then you can likely skip the port forwarding step, but you will still need to open the ports in your Windows Firewall more than likely if you’re on PC. This is especially true if you have a third-party firewall such as an anti-virus firewall.

Check your NAT type

To check your NAT type in Modern Warfare 3: Simply open MW3, and head to the Settings menu. On Accounts and Network, click Network Info, and you should immediately see if you need to go further in this guide.

DO NOT open this screen if you’re streaming. It shows your public IP address in plain view. Streamer mode does not hide this info – It really should, though!

There are 2 main steps to opening your NAT type for MW3, or any game. They are as follows.

Allow MW3 through your firewall

If you’re using an antivirus, the steps will be different. Things are simple and explained below if you’re not using anything extra or any other kind of firewall. Simply put: We need to tell your computer to explicitly allow all traffic over specific ports so nothing is blocked. We can do so via the Windows Firewall settings program, included with all Windows systems.

There is a very easy way to do this if you have access to PowerShell and can run it as Admin (Most systems will have this). Hit Start and search for PowerShell, and run it as admin. Then copy and paste the following commands in, hitting Enter a few times afterwards to make sure everything has run properly.

1 2 3 4 5 6 7

$tcpPorts = '3074', '3075', '27015-27030', '27036-27037' New-NetFirewallRule -DisplayName "MW3" -Direction Inbound -Protocol TCP -LocalPort $tcpPorts -Action Allow New-NetFirewallRule -DisplayName "MW3" -Direction Outbound -Protocol TCP -LocalPort $tcpPorts -Action Allow $udpPorts = '3074', '4380', '27000-27036' New-NetFirewallRule -DisplayName "MW3" -Direction Inbound -Protocol UDP -LocalPort $udpPorts -Action Allow New-NetFirewallRule -DisplayName "MW3" -Direction Outbound -Protocol UDP -LocalPort $udpPorts -Action Allow

If you ever wish to remove your Firewall rules for this, run the command: Remove-NetFirewallRule -DisplayName "MW3"

You should now be able to skip to the next step. The manual section below is only for users who can’t get it to work with the above.

Otherwise, the manual steps are:

1. Press Start, and search for Windows Firewall. Open Windows Firewall with Advanced Security.
2. On the left, click Inbound Rules.
3. On the right, click New Rule.
4. Select Port, click Next.
5. Choose TCP, and enter into “Specific local ports”: 3074,3075,27015-27030,27036-27037, Next.
6. Make sure Allow this connection is selected. Click Next.
7. Enter any name into the Name section, and click Finish.

Now, all we need to do is rinse and repeat steps 2 through 7, but for step 5 choose UDP and enter the ports: 3074,4380,27000-27036.

Then, head to Outbound Rules on the left, and we’ll redo everything one last time.

Create new rules for:

• TCP: 3074,3075,27015-27030,27036-27037
• UDP: 3074,4380,27000-27036

Now we can close out of the firewall app and continue to our router. This is where things get a little confusing, but hopefully, the video can guide you further if necessary.

Port forwarding Modern Warfare 3

You don’t need to complete this step if you have UPnP enabled and set up. Port-forwarding should be automatically handled by your system and router.

Open your router’s config page, and log in. If you are unsure of your login details, contact your ISP for steps to get them or resetting.

To get your router’s address to navigate to in your browser - on Windows:

• Press Start and type CMD. Then open Command Prompt, or Terminal on Windows 11.
• Type ipconfig, and press Enter.
• Now, look for how you’re connected to the internet. It’s likely either Wireless..., or Ethernet....
• Look at the Default Gateway. This is your router’s IP address, and you simply need to navigate to it in your browser like you would any other website.

Once on your router’s config page and signed in, look for Port Forwarding or Application Forwarding. First we can enter a list of ports; second, we can create an app and enter ports there - Then point it to our computer’s local IP address later.

Enter the ports we used earlier. The complete list of ports is below for other platforms too. You will likely need to enter single ports or ranges of ports. For standard ports between TCP and UDP, you can probably select TCP/UDP` or a similar option in your router. Otherwise, you will need to enter the same ports for both types.

The Port Forwarding/Application Forwarding section should look something like this:

Ports for Call of Duty: Modern Warfare 3:

PC:

• TCP: 3074,3075,27015-27030,27036-27037
• UDP: 3074,4380,27000-27036

Playstation 4/5:

• TCP: 1935,3074,3478-3480
• UDP: 3074,3478-3479

Xbox One/Series X:

• TCP: 3074
• UDP: 88,500,3074,3544,4500

When complete, your router should look like the following example:

Now, you can simply relaunch the game and check your NAT type, as explained previously. It should now show as open.

If it didn’t work

• Call your ISP and see if they allow or need to enable port forwarding. I had to do this, as unlikely as it seems.
• Check if any other firewall is interfering with your game.
• Temporarily disable Windows Firewall or your AntiVirus firewall to see if they are causing an issue.
• If you want help port-forwarding you can follow this simple guide I’ve created on YouTube.
• If you have more than one router between you and the internet, you must follow a multi-router port forwarding guide. I have created a simple breakdown of one here on YouTube.