What is Double NAT and how do I fix it?
Double NAT happens when two routers on your network are both performing Network Address Translation (NAT). This can cause issues with services that require direct internet access, such as online gaming, CCTV systems, port forwarding, or remote access tools.
What is NAT?
NAT (Network Address Translation) is a feature used by your router that allows multiple devices in your home to share a single public internet IP address.
This is how your home network connects multiple devices — such as phones, laptops, and smart TVs — to the internet using one connection.
What is Double NAT?
Double NAT occurs when two routers on the same network are both performing NAT.
This usually happens when a second router or networking device is connected behind your main router.
When this happens, your internet traffic passes through two separate routers, which can cause certain services to stop working correctly.
What causes Double NAT?
Double NAT usually happens when:
- You connect your own router behind your ISP router
- A modem/router combo device is connected to another router
- A mesh WiFi system is set to router mode instead of access point mode
- A WiFi extender is configured as a router
In most home networks, only one device should manage routing and NAT.
Signs you may have Double NAT
You may be experiencing Double NAT if you notice:
- Strict or Moderate NAT type in online games
- Port forwarding not working
- Remote access to devices failing
- CCTV or smart home systems not connecting properly
Another sign is when your router receives a private IP address on its WAN connection.
Private IP ranges include:
- 192.168.x.x
- 10.x.x.x
- 172.16.x.x – 172.31.x.x
Problems Double NAT can cause
Double NAT does not usually affect basic browsing or streaming, but it can cause problems with services that require direct inbound connections.
This may include:
- Online gaming
- Remote access to home devices
- CCTV systems
- VPN connections
- Home servers
- Port forwarding
- Some smart home features
How to fix Double NAT
The most common ways to resolve Double NAT include:
- Set your second router or mesh system to Access Point Mode
- Enable Bridge Mode or Modem Mode on one router
- Remove the additional router and use only one device for routing
- Ensure mesh systems are operating in Access Point Mode instead of Router Mode
In most cases, only one device on your network should perform NAT.