CGNAT Check

Router help

How to find your router WAN IP

Look for the WAN, internet, broadband, or external IPv4 address in your router or ISP gateway status page. That internet-facing value is what the checker needs.

Compare your IPs

What the checker actually needs

The checker needs the IPv4 address shown on the internet-facing side of your router or gateway. That field may be labeled WAN, Internet, Broadband, Status, Connection, IPv4, or External IP.

It is usually not the IPv4 address shown on your PC, phone, or Wi-Fi device. Those local addresses often start with 192.168, 10, or 172.16 to 172.31 because they belong to your home LAN, not the upstream internet side of the router.

A Default Gateway or Router address is also not automatically the WAN IP. It only identifies where your device sends traffic next and may help you reach an admin page. Enter a value into the checker only when the router or gateway identifies it separately as WAN, Internet, Broadband, Cellular, or External IPv4.

Once you have that WAN value, run the CGNAT Checker and compare the result with the CGNAT explainer if you need more background.

Windows

Use `ipconfig` to find the router

  1. Open Command Prompt.
  2. Run ipconfig.
  3. Find the Default Gateway value for the active adapter.
  4. Use that gateway address only to try to open the router or ISP admin page.
  5. Sign in if the page is available.
  6. Look for a page such as Status, Internet, WAN, or Broadband.
  7. Copy the WAN or Internet IPv4 shown there into the checker.

The PC's own IPv4 from ipconfig is usually just a LAN address. That is normally not the value the checker needs. The Default Gateway is not a substitute for the WAN IP either.

macOS

Use Network settings to find the router

  1. Open System Settings, then Network.
  2. Open the active Wi-Fi or Ethernet connection.
  3. Find the Router address in the connection details.
  4. Use that address only to try to open the admin page in a browser.
  5. Sign in to the router or gateway admin page.
  6. Locate the WAN, Internet, Broadband, or IPv4 status field.
  7. Copy the WAN or Internet IPv4 into the checker.

macOS labels and submenu names can vary a little by version, but the basic goal is the same: find the router address for the active network and use that to reach the admin page.

Linux

Use `ip route` to find the gateway

  1. Open Terminal.
  2. Run ip route.
  3. Find the address shown after default via.
  4. Use that address only to try to open the router or gateway admin page.
  5. Sign in to the router or gateway admin page.
  6. Find the WAN, Internet, Broadband, or IPv4 status page.
  7. Copy the WAN or Internet IPv4 into the checker.

iPhone and iPad

Use the Router field in Wi-Fi settings

  1. Open Settings, then Wi-Fi.
  2. Tap the connected network.
  3. Find the Router address.
  4. Use that address only to try to open the admin page in Safari.
  5. Sign in if the router or gateway page is available.
  6. Find the WAN, Internet, Broadband, or IPv4 status page.
  7. Copy the WAN or Internet IPv4 into the checker.

The Router field helps you reach the admin page. It is not automatically the same thing as the WAN IP you need to compare.

Android

Find the gateway from Wi-Fi details

  1. Open the details for the Wi-Fi network you are currently using.
  2. Look for the router, gateway, or similar network field if the phone exposes it.
  3. Use that address only to try to open the router or gateway admin page.
  4. Sign in to the router or gateway admin page.
  5. Locate the WAN, Internet, Broadband, or IPv4 status field.
  6. Copy the WAN or Internet IPv4 into the checker.

Android menus vary by manufacturer and version, so the exact labels may differ even when the basic path is the same.

Phone hotspot or tethering

The phone's gateway may not expose a WAN IP

When a computer connects through a phone hotspot, the path is usually:

computer -> phone hotspot -> mobile carrier -> public internet

For example, ipconfig might show the PC as 10.186.104.253 and the Default Gateway as 10.186.104.203. The first value is the computer's local hotspot address. The second is normally the phone or hotspot-side gateway. Neither should automatically be treated as the carrier-facing WAN IPv4.

Many phones do not provide a traditional router admin page or reveal the carrier-side WAN IPv4. CGNATCheck can still show the public-facing IP visible from the internet, but the normal comparison may not be possible. Check any available mobile network or hotspot information, or ask the carrier whether the connection receives a public IPv4 address. Policies can vary, so a mobile connection should not be assumed to use CGNAT without further evidence. See the CGNAT explainer for the signs that are more useful than the hotspot gateway alone. The dedicated mobile hotspot, 4G and 5G guide covers what to ask a carrier when the WAN value is hidden.

Dedicated 4G or 5G router

Check the cellular router's status page

A dedicated cellular router may have a normal browser or app-based admin interface. In its connection status, look for a field such as:

  • Mobile WAN IP
  • Internet IPv4
  • Cellular IPv4
  • WAN address

Use the address explicitly shown in one of those internet-facing fields. Do not copy the gateway address used merely to reach the router interface.

Admin-page fallback

Router or gateway page won't open?

An unavailable page does not turn the Default Gateway into a WAN IP. The gateway may be a phone hotspot, the device may be managed only through an app, the ISP gateway may not expose a browser interface, or HTTP access may be disabled. Workplace, hotel, and public networks can also be managed upstream, where you have no access to the WAN details.

  • Confirm that the gateway belongs to the adapter currently providing internet access.
  • Try HTTPS as well as HTTP when opening the gateway address.
  • Check whether the ISP or router manufacturer provides a management app.
  • Do not enter the Default Gateway into CGNATCheck if the admin page cannot be reached.
  • On a managed or public network, accept that upstream WAN information may not be available to you.

Common labels and common mistakes

  • Router interfaces vary a lot, so check pages named WAN, Internet, Broadband, Status, Connection, IPv4, or External IP.
  • If you see both a local device IPv4 and a WAN or Internet IPv4, the WAN or Internet field is usually the one the checker wants.
  • A private WAN range such as 192.168.x.x, 10.x.x.x, or 172.16-31.x.x often means another router or gateway exists upstream.
  • A WAN value in 100.64.0.0 to 100.127.255.255 is a stronger shared-address signal that often points toward CGNAT.
  • If the router only shows IPv6, the checker can still be informative, but it cannot fully confirm the IPv4 path from browser data alone.

If you need to check an unfamiliar value, use the public, private, and CGNAT IPv4 reference.

If port forwarding still fails after you find it

A clean WAN IP check is only one part of the picture. If inbound traffic is still failing, use the Port Checker for a best-effort public reachability test, then work through why port forwarding fails or the NAT Type Check page if the issue shows up in games or peer connectivity.

Brand-specific help

Router guides

View all router guides

TP-Link

How to find the WAN IP on TP-Link routers

Find the internet-facing address on TP-Link routers so you can compare it with your public IP.

Read more

eero

How to find the WAN IP on eero systems

A simple guide to locating the WAN or internet IP in eero so you can compare it against your public IP.

Read more

Once you have the WAN IP

Decide whether you need a fix or a workaround

A private or shared WAN IP often points toward another NAT layer, but the exact meaning matters. Run the checker, compare the result with what CGNAT means, and then review solution paths only after you know whether you are dealing with shared IPv4, double NAT, or a simple router-path mistake.