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Troubleshooting Strict NAT: Why You Keep Getting It and How to Fix It

Troubleshooting Strict NAT: Why You Keep Getting It and How to Fix It

Are you constantly running into Strict NAT type warnings when gaming online or using peer-to-peer applications? You're not alone.

Strict NAT can cause connectivity issues, limit your multiplayer gaming experience, and prevent remote access to your devices. In this guide, we'll break down why this happens and what you can do to fix it.

🔍 What Does Strict NAT Mean?

Strict NAT (often caused by Symmetric NAT) is the most restrictive form of NAT configuration. It limits your device to:

  • Only initiating outbound connections
  • Rejecting incoming unsolicited connections
  • Preventing certain peer-to-peer or multiplayer connections

This can severely impact:

  • Voice chat
  • Game invites
  • Co-op or matchmaking
  • Remote desktop or camera access

🧠 Why Do You Keep Getting Strict NAT?

Here are the most common causes:

1. 🚫 Your ISP Uses CGNAT (Carrier-Grade NAT)

Your internet provider may be placing you behind a shared public IP with other customers. This setup blocks inbound connections completely.

🛠️ Solution: Contact your ISP and request a dedicated public IP address.

2. 📶 Double NAT Setup

If you're using a modem/router combo and then connected another router (like a mesh system), you're probably behind two layers of NAT.

🛠️ Solution:

  • Put one of the devices in bridge mode
  • Use only one router for routing
  • Or configure DMZ to pass all traffic through

3. 🔒 UPnP Is Disabled

UPnP (Universal Plug and Play) automatically opens the ports needed for applications like games or VoIP. If it’s off, NAT becomes stricter.

🛠️ Solution: Enable UPnP in your router settings. Be sure to save and reboot.

4. 🔁 Port Forwarding Is Missing

Some services require manual port forwarding. Without it, strict NAT remains.

🛠️ Solution: Find out which ports your game or service needs and forward them in your router.

5. 🔥 Firewall Rules or ISP-Level Filtering

Some firewalls or ISPs block ports used for peer-to-peer connections.

🛠️ Solution: Check firewall settings on your router. If you're on a corporate or school network, restrictions may be outside your control.

🛠️ How to Fix Strict NAT (Step-by-Step)

  1. Log into your router's admin page (typically 192.168.0.1 or 192.168.1.1)
  2. Check if you're behind Double NAT (compare WAN IP vs. public IP)
  3. Enable UPnP
  4. Set up Port Forwarding or DMZ if needed
  5. If still strict, consider:
    • Switching to a different router
    • Requesting a public IP from your ISP
    • Using a VPN that supports port forwarding (e.g., PureVPN, Mullvad)

🧪 Want to Test Your NAT Type Right Now?

Use our free online tool to detect your NAT behavior and see whether you’re Open, Moderate, or Strict:

👉 Check NAT Type at whatsmynat.com

✅ Final Thoughts

Strict NAT doesn’t mean your internet is broken—it just means your device is having a hard time talking to the outside world.

By understanding the underlying causes and configuring your router properly, you can often fix the issue in minutes and drastically improve your online experience.

🎮 Game better. Connect faster. Diagnose smarter.