You plug in a new eero, and the setup finishes. But your ISP’s box still broadcasts its own Wi-Fi, and you wonder if two routers will fight each other.
An eero double NAT setup means two routers both do the routing. One example is your ISP’s modem/router combo with the eero behind it. eero says the better fix is to put the combo in bridge mode, not the eeros. Bridging the eeros is for a small group of setups. It costs you profiles, port forwarding and UPnP.
This guide sorts the choices using eero’s own support pages. It also covers what eero’s pages leave out.
What an eero Double NAT Setup Means
NAT lets many devices share one public IP address. eero’s NAT page says double NAT “creates two separate networks by having two routers perform NAT.”
An eero double NAT setup is not always a fault. The page doesn’t call it a problem. But it does recommend bridge mode for a modem/router combo.
It’s also worth knowing what the page doesn’t say. It doesn’t describe symptoms, and it doesn’t explain how eero detects double NAT. So I can’t tell you what an alert looks like, only what eero recommends.
Step 1: Work Out Which Equipment You Have
Your fix depends on what sits in front of the eero.
| What you have | eero’s recommended approach |
|---|---|
| Modem only (no router built in) | Connect the gateway eero to the modem, as the app suggests |
| Separate modem and router | Connect the gateway eero to your existing router, then finish setup |
| Modem/router combo | Connect the eero to the combo, then optionally bridge the combo |
Wait before you reach for the eero’s bridge setting. eero’s bridge mode page says that for a modem/router combo, you should bridge that device rather than your eeros.
Fix 1: Put the Modem/Router Combo in Bridge Mode
eero defines bridge mode like this: “Bridge mode disables a device’s routing and wifi capabilities.” The device then works “only as a modem or access point.” On the ISP box, the eero does the routing and the combo acts as a modem.
How to approach it:
- Connect the gateway eero to the combo and complete setup
- Find the bridge mode option in your ISP device’s settings
- Turn it on, or ask your ISP how
eero’s NAT page calls this step optional. Its bridge page gives the same advice. Menu names vary by device, and the pages don’t give brand-specific steps.
If your combo has no bridge mode, eero has a fallback. Turn off Wi-Fi on the ISP equipment and bridge your eeros instead. Also use a different network name and password on the eero. eero says two networks with the same name “will lead to technical complications.”
Fix 2: Connect the eero to Your Existing Router
If you own a separate router you want to keep, eero’s NAT page gives a different path. Don’t connect the gateway eero to the modem as the app suggests. Connect it to your existing router, then finish setup in the app.
This creates an eero double NAT on purpose. eero’s own page lists it as a valid setup.
Fix 3: Bridge the eeros Only When You Must
eero says bridging the eeros is necessary for a small subset of customers. Its examples are AT&T U-Verse, ISPs that need PPPoE, and ISPs that need a specific MAC address. It also says it generally doesn’t recommend this approach.
How to switch (eero app):
- Open your network and tap Settings
- Tap Advanced networking
- Under Network services, tap DHCP & NAT
- Change the selection from Automatic to Bridge
eero adds three warnings. One eero must stay wired to your network by Ethernet. All connections must pass through that gateway eero. And returning to Automatic restarts the network, so devices may need to reconnect.
What You Lose When You Bridge the eeros
The support.com guide I checked says only that you “will lose many advanced features” and doesn’t name them. eero’s bridge mode features page lists the losses.
- Profiles
- Historical data usage details
- Device blocking
- IP reservations and port forwarding
- Local DNS caching, Smart Queue Management and Thread
- Upstream IPv6, custom DNS and UPnP
- Most eero Plus features, apart from Malwarebytes, 1Password and Guardian VPN
- Apple HomeKit Secure Router
What stays: eero says you’ll still get the speed and stability benefits of TrueMesh. You also keep managing the network through your existing router.
If you use port forwarding, IP reservations or profiles, bridging the combo instead is the better route. That is my reading of the two lists together.
An Unresolved Case: PPPoE and Old Advice
PPPoE is a login method some ISPs use. Older advice says eero can’t handle it, so you must bridge.
A community thread shows this. A user with a CenturyLink Actiontec C1000A said PPPoE blocked a simple bridge. The replies came from other users, not eero staff. The page shows the thread as about five years old.
The advice didn’t solve it. The poster ended the double NAT by switching ISPs.
eero’s pages have since changed. The bridge page says PPPoE support was added for eero Pro 6 and eero 6. It names eeroOS v6.6.1 and app version 6.13.0. The offline page lists PPPoE under Settings and ISP Settings. You enter the details “exactly as your ISP documents them.”
But the bridge page still names PPPoE providers as a case where bridging the eeros is needed. So the two statements conflict. Check with your ISP, and test before you assume either one.
When an eero Double NAT Might Matter
eero’s pages don’t list symptoms. As general networking, two routers can break port forwarding and device discovery across the two networks. That is not an eero statement, and results vary.
Say your phone can’t find a speaker or Chromecast. Then see our no cast devices found guide. Our guide to Sonos speakers that vanish from the app helps too. Our best router settings for smart home devices guide covers the shared settings. Smart cameras can drop too, as our Wyze camera offline after wifi change guide shows.
Frequently Asked Questions
What is an eero double NAT? It means two routers both perform NAT on your network. eero describes it as creating two separate networks. eero doesn’t call it a fault.
Should I bridge my eero or my modem? eero recommends bridging a modem/router combo rather than the eeros. Bridging the eeros is for a small set of setups, such as AT&T U-Verse or PPPoE ISPs.
How do I put an eero in bridge mode? Go to Settings, Advanced networking, then DHCP & NAT. Change Automatic to Bridge. eero generally doesn’t recommend this.
What do I lose in eero bridge mode? You lose profiles, device blocking, port forwarding, IP reservations, UPnP, custom DNS and most eero Plus features. TrueMesh benefits stay.
Do I need a different Wi-Fi name for the eero? Yes, eero says to use a different SSID and password. Two networks with the same name cause technical complications.
The Bottom Line
An eero double NAT setup is fixed best by bridging the ISP’s modem/router combo, not the eeros. eero says to bridge the eeros only for setups such as AT&T U-Verse, PPPoE providers or MAC-bound ISPs. Doing so costs you profiles, port forwarding, IP reservations, UPnP and more. These steps come from eero’s support pages, which show no dates and don’t describe symptoms. Change one setting at a time, and note your old settings so you can undo them.