Wi-Fi & routers

Multiple routers in the same house are causing problems

Running two routers, such as your ISP's modem-router combo alongside your own router, can create a 'double NAT' situation that causes connectivity issues, and the fix is usually to put one device into bridge or access-point mode.

Difficulty
Advanced
Time
20–45 minutes
DIY cost
$0
Pro cost
$0–$100

Symptoms

  • Some devices connect fine while others have intermittent issues
  • Online gaming, video calls, or certain apps behave oddly or show connectivity errors
  • Port forwarding or a VPN server doesn't work correctly
  • Two different networks show up with different names from what seems like one setup

Likely causes

  • CommonBoth an ISP-provided modem-router and a personal router are acting as full routers (double NAT)Having two devices both performing network address translation can break certain types of connections, especially for gaming, VoIP, and hosting servers.
  • PossibleOld and new routers both still active on the networkAn old router left plugged in after an upgrade can create confusing overlapping networks.
  • PossibleTwo networks in the house set up independently without coordinationFor example, a household with two internet-connected devices trying to both serve as the main router.

What to do

  1. Identify how many devices in your setup can act as a router (check if your ISP's modem is actually a modem-router combo, which is common).
  2. Decide which single device should be the main router; typically your own router offers better features than the ISP's combo unit.
  3. Log into the ISP's modem-router and switch it to 'bridge mode' if it offers that option, which disables its routing function and lets your own router handle everything.
  4. If bridge mode isn't available, connect your own router's WAN port to one of the ISP device's LAN ports, and accept that some advanced features like port forwarding may need configuring on both devices.
  5. Disconnect and unplug any old router that's no longer needed to avoid unnecessary duplicate networks.
  6. Restart all devices in the correct order: modem first, then the single active router, then everything else.
  7. Test that port forwarding, gaming, or VoIP issues are resolved once you're down to a single routing device.

Tools and parts

  • Ethernet cable
  • Access to both devices' admin pages

When to call a pro

If your ISP's modem-router doesn't support bridge mode or you're unsure how to configure it, your ISP's technical support can usually enable this remotely or walk you through it.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.