Double NAT means two routers are each doing address translation — usually your provider's modem-router and your own router. Everyday browsing works, but VPNs, VoIP, and anything needing incoming connections can break. Putting the provider's device in bridge mode, or your router in access point mode, removes one layer.
Common causes
Provider modem is also a router
Many provider devices combine a modem and router, and your own router adds a second layer.
Extra router added for WiFi
Plugging a consumer router into the office network to add WiFi creates a second network inside the first.
Mesh system in router mode
Mesh WiFi kits often default to router mode even when another router exists.
How to fix it, step by step
- 1
Check your router's WAN address
If the router's WAN IP starts with 192.168, 10., or 172.16–31, there's another router in front of it.
- 2
Put the provider device in bridge mode
Ask your provider or use the modem's settings to switch it to bridge or passthrough mode.
- 3
Or set the second router to access point mode
If the extra router is only there for WiFi, switch it to access point (bridge) mode.
- 4
Use the provider's DMZ/IP passthrough if needed
If bridge mode isn't available, pass all traffic to your router as a fallback.
- 5
Restart and retest
Restart both devices and confirm your router now gets a public IP address.
When to call a technician
Changing modem modes can take the office offline if done wrong. We plan the change, coordinate with your provider, and make sure VPN, phones, and cameras work afterward.
On-site support across Orange County · see our business networking and WiFi installation services.
Frequently asked questions
Is double NAT bad?
For basic browsing it's fine, but it causes problems for VPNs, VoIP, gaming, cameras, and port forwarding. In an office it's best avoided.
What is bridge mode?
Bridge mode turns off the routing features of the provider's modem so it only passes the connection to your router.
Will bridge mode turn off the provider's WiFi?
Usually yes. Your own router or access points then handle WiFi, which is what you want.