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🎮 NAT and Gaming

Double NAT with Phone Tethering What Breaks for Gaming VPN and Port Forwarding

Everything browses fine on your phone-fed router — until a game shows a strict NAT type, the office VPN will not connect, or your camera is unreachable from outside. This page explains the NAT stack you are actually behind, in plain terms, and what can and cannot be fixed.

✍️ Technical Anshu📶 Phone Internet on Router⏱️ 7 minute read
🎥 The complete phone-to-router tethering setup, shown step by step in the video

NAT is the translation your router does so many private devices can share one public address. With phone tethering, the translation happens two or three times: your router translates, the phone translates again, and most mobile networks add CGNAT — carrier-grade NAT — because they do not have a public IPv4 address for every customer. Outbound traffic does not mind at all. Anything that needs the internet to reach into your network minds a great deal. Here is the honest map.

The NAT Layers Between Your Device and the Internet
💻 Your device192.168.x.x private address
📡 Home router NATLayer 1 — your router translates
📱 Phone NATLayer 2 — the phone translates again
🏢 Carrier CGNATLayer 3 — the mobile network translates too
🌐 InternetSees only the carrier address
Outbound traffic (browsing, calls, streaming) passes all layers fine. Inbound connections have no way back through them.

Three translation layers is normal on a phone feed — this is a property of mobile networks, not a fault in your setup.

1

What Keeps Working Perfectly

  1. Browsing, streaming, downloads, software updates, cloud apps and billing software
  2. Video calls and messaging — they all dial out and hold the connection open
  3. Most online games actually playing — matchmaking and gameplay are usually outbound-driven
  4. Incoming VPN connections that your devices initiate to an office server (the tunnel is outbound-started)

If your use is in this list, you can stop worrying about NAT entirely. The majority of home and office use lives here.

2

Gaming — the NAT Type Problem

Consoles and some PC games judge the connection and report NAT Type 3 / Strict. Party voice chat may fail, hosting a game session rarely works, and peer-to-peer matchmaking gets slower or pickier. The cause is the layered translation — your router's UPnP can open ports through layer one, but the phone and the carrier do not honour those requests. The honest options: accept strict NAT for casual play, play over the phone's own hotspot directly (removes one layer, CGNAT remains), or use a gaming VPN service that provides its own tunnel endpoint. No router setting removes CGNAT — any guide promising a setting for that is selling false hope.

3

Port Forwarding and Remote Access — Mostly Closed

  1. Port forwarding will not work in the normal case: there is no public address on your side to forward from — the carrier holds it and shares it among many customers
  2. CCTV / NVR viewing works only through the manufacturer's cloud relay (the app connects out to their server), not by direct IP
  3. Remote desktop into your network needs a tool that dials out — Tailscale-class mesh VPNs or remote-support tools — rather than an open port
  4. Asking the carrier for a public IP is the one real fix where offered: some providers sell a public-IP add-on or a business APN. Worth one phone call before buying other gear
4

VPN in Both Directions, Honestly

A VPN your laptop starts to reach your office (outbound) works fine through the NAT stack — this is the common case and it simply works. A VPN server hosted inside your network for people to connect into (inbound) is the broken case, for the same reason as port forwarding. The modern workaround is a mesh VPN such as Tailscale or ZeroTier-class tools: every device dials out to a coordination service and the tunnel is built from inside, so NAT layers stop mattering. For a small office running on a phone feed, that pattern is the standard answer.

5

Can You Remove a Layer?

  1. Phone tethered straight to one computer = one NAT layer fewer than the full router chain — fine for a single-device setup
  2. A travel router adds its own NAT; putting the main router in access-point mode removes the main router's layer and keeps its Wi-Fi
  3. Nothing on your side removes the carrier's CGNAT layer — it is inside the mobile network
  4. Chasing a perfect NAT type on a mobile feed is a losing project; route around it with outbound-based tools instead
🔴 The one-line truth: on a phone-fed network, design everything to dial out — mesh VPNs, cloud relays, remote-support tools. Anything designed around the internet dialing in will keep disappointing you, and it is the carrier's architecture, not your equipment.

🎥 Watch the Full Setup in the Video

The wiring, the router settings and the live speed check — the complete process is shown in the video.

▶ Watch Full Video
❓ Common Questions (FAQ)

Why does my game show NAT Type 3 or Strict?

Because your connection passes through multiple NAT layers — your router, the phone, and the mobile carrier's CGNAT. UPnP and port settings on your router only control the first layer, so the game still sees a restricted connection. It is normal on mobile internet and not a fault in your router.

Can I port forward to my camera or PC on a phone connection?

In the normal case, no. Your network has no public IP address of its own — the carrier shares one among many customers through CGNAT, so there is nothing to forward from. Use the camera maker's cloud app, or a mesh VPN like Tailscale for your own devices.

Does a VPN fix the NAT problem?

A commercial VPN gives you its own endpoint, which can help some gaming and geo cases, and a mesh VPN (Tailscale class) genuinely solves remote access by building tunnels from inside. But a VPN does not give your network a true public IP with open ports unless the provider specifically sells that feature.

This guide is based on the Technical Anshu video above • Stuck on a step? Ask in the video comments — questions get answered there 🙏