Two routers each translating addresses in a row. Most websites work, but port forwarding, some games and VPNs can break.

Is it safe to put my router behind the ISP one?

Yes. Change the admin password on both devices.

Using Your Own Router with an ISP Router: Avoid IP Conflicts

How to connect your own router to an ISP router or ONT without address conflicts, what double NAT is, and when to ask for bridge mode.

Many people plug a better router into the ISP’s router. If both use the same address range, such as 192.168.1.x, the network breaks or you cannot reach the ISP page. The fix is to give your router a different range.

Your own router behind the ISP router must use a different address range, such as 192.168.2.1 instead of 192.168.1.1

Step-by-step setup

Connect a computer to your own router and open its admin page.
Change its LAN address so it is in a different range from the ISP device. If the ISP router uses 192.168.1.1, use 192.168.2.1.
Plug a cable from a LAN port on the ISP router into the WAN or Internet port on your router.
Set your router’s WAN type to DHCP (automatic).
Turn off Wi-Fi on one of the two devices, or give them different names, so phones do not hop between them.
To open the ISP router page later, connect to it directly.

Three ways to connect

Method	What it means	When to use it
Router behind router	Your router makes its own network behind the ISP’s	Easiest, but causes double NAT
Bridge mode on the ISP device	The ISP device just passes the connection through	Best for gaming and port forwarding. Ask your ISP if they allow it
Access point mode on yours	Your router adds Wi-Fi only, with no routing	Best if you only want better Wi-Fi coverage

Common problems

Port forwarding does not work: Double NAT blocks it. Forward the port on both devices, ask the ISP for bridge mode, or use access point mode.
I cannot open the ISP router page: It sits behind your router now. Connect a cable straight to the ISP device, or set a static address in its range.
The internet stops after I connect: The two devices use the same range. Change your router’s LAN address as shown above. The subnet calculator shows the range for any address.
Some ISPs lock the ONT: You may not be able to change much on the ISP side. See Fibre ONT login.

Questions people ask about Own router behind ISP router

What is double NAT?: Two routers each translating addresses in a row. Most websites work, but port forwarding, some games and VPNs can break.
Is it safe to put my router behind the ISP one?: Yes. Change the admin password on both devices.

Last checked 2026-10-03. Default logins differ by model, so always check the label on your router first. Sources: RFC 1918: private address ranges

Free tools that help

Subnet calculatorEnter an IPv4 address with a prefix or netmask to get the network, broadcast, host range, wildcard mask and usable hosts. Split into subnets.