How Cloudflare can help a request find your Raspberry Pi
Short answer: it can 100% work—but you’re missing a few gnarly-but-solvable pieces between “scan ring” and “serve a page from a Pi behind home Wi-Fi.”
Here’s the reality checklist, then a working skeleton you can deploy today.
Below is a fully working starter you can drop on a Pi. It includes:
Your home router does this.
Problem: unsolicited inbound packets (like someone hitting
Your ISP’s version of NAT for whole neighborhoods.
Result: you can’t host anything that needs to accept inbound connections directly from the Internet.
No amount of
“Traversal” means getting packets through those NAT walls.
Common methods:
Cloudflare Tunnel (
No ports opened
No static IP needed
Works through NAT and CGNAT
TLS handled automatically
From the Internet’s perspective, your Pi is invisible — Cloudflare’s edge is your public face.
Add these layers to make the scan secure and cloudflare-compatible:
So yes — Cloudflare solves your missing part.
It becomes the secure middleman between the outside world and your bedroom-humming Raspberry Pi, letting your Empire Ring authentication system work from anywhere without fighting NAT or your ISP.
no new hardware and no modification to your Wi-Fi account or router.
That’s the whole magic of Cloudflare Tunnel (aka Argo Tunnel /
Let’s unpack this clearly so you know exactly what happens and why you don’t need to buy or rewire anything.
Cloudflare Tunnel flips the connection inside-out.
Instead of the Internet trying to reach into your Pi (which fails because NAT/CGNAT block it),
your Pi reaches out to Cloudflare’s network and keeps a permanent, encrypted tunnel open.
That one outbound HTTPS/WebSocket connection can carry all inbound web traffic safely back down to your Pi.
Outbound traffic always works through your ISP’s firewall/NAT, so it needs no permission, no ports, no static IP, and no router access.
You just need:
→ hits Cloudflare’s edge
→ travels down the encrypted tunnel
→ lands on your Pi at
→ Nginx or Django serves it back up the same route.
In short:
Short answer: it can 100% work—but you’re missing a few gnarly-but-solvable pieces between “scan ring” and “serve a page from a Pi behind home Wi-Fi.”
Here’s the reality checklist, then a working skeleton you can deploy today.
What you’re missing (and how to nail it)
- NAT / CGNAT traversal
- If you simply create an
Arecord to your home IP, you also need: a static public IP, router port-forwarding (443→Pi), and your ISP must not be using CGNAT. - Easiest: Cloudflare Tunnel (
cloudflared) from the Pi → Cloudflare edge. No ports opened. Your domain points to the tunnel.
- If you simply create an
- TLS termination & certs
- With a raw
Arecord, you’d terminate TLS at Nginx on the Pi and manage ACME/Let’s Encrypt. - With Tunnel: Cloudflare terminates TLS at the edge, and the tunnel uses mTLS to your Pi. Simpler + safer.
- With a raw
- Zero-Trust gate in front of your app
- Put Cloudflare Access (Zero Trust) in front of your origin route. This gives you WAF, rate limiting, device posture checks, IP rules, and a pre-auth wall before your code even runs.
- Identity & ring attestation
- Scanning the Empire Ring should produce a nonce-bound assertion (not just an ID string). Store a per-login challenge, verify replay, and bind it to a session/JWT.
- Use WebAuthn semantics (FIDO2) where possible: the ring acts like a security key (even if we abstract it through your NFC middleware). At minimum: HMAC + rolling counter + timestamp + nonce.
- Replay protection & time
- Every ring scan must include a server-issued nonce and a monotonic counter inside the ring payload. Enforce 5–15s TTL, and reject replays / skew. Keep your Pi clock synced (chrony).
- Origin shielding & firewall
- Your Pi should not be reachable from the public internet. Only Cloudflare Tunnel connects in. Block LAN→WAN inbound except the tunnel.
- Queueing & backpressure
- Don’t do heavy work in the request thread. Verify ring → enqueue work → respond. Use RabbitMQ/MQTT and worker processes.
- Observability & ops
- Health endpoints, structured logs, metrics, error tracking, UPS on the Pi, watchdog to auto-restart services, and regular, tested backups.
- Database & secret
- Never let a browser talk directly to the DB. Secrets in env vars or a file protected by filesystem ACLs. Rotate keys.
- Versioning & idempotenc
- All ring events should be idempotent (same scan won’t double-create sessions). Version your API and your ring payload schema.
Minimal, production-lean path (recommended)
Pattern: Domain → Cloudflare Edge (TLS/WAF/Zero-Trust) → Cloudflare Tunnel → Nginx on Pi → App (FastAPI sample below; swap for Django later).Below is a fully working starter you can drop on a Pi. It includes:
- Cloudflare Tunnel config
- Nginx reverse proxy
- FastAPI service with JWT login via ring scan, nonce, replay protection, and a protected
/whoamiroute - Docker Compose so it’s one command to run
File list
Code:
empire-node/
├─ docker-compose.yml
├─ nginx/
│ └─ nginx.conf
├─ cloudflared/
│ └─ config.yml
├─ app/
│ ├─ Dockerfile
│ ├─ requirements.txt
│ ├─ main.py
│ ├─ config.py
│ ├─ db.py
│ ├─ models.py
│ ├─ auth.py
│ ├─ ring.py
│ └─ security.py
└─ .envdocker-compose.yml (Pi)
Code:
version: "3.9"
services:
app:
build: ./app
env_file: .env
restart: unless-stopped
networks: [internal]
healthcheck:
test: ["CMD", "curl", "-fsS", "http://localhost:8000/health"]
interval: 15s
timeout: 3s
retries: 5
start_period: 10s
nginx:
image: nginx:1.27-alpine
depends_on: [app]
volumes:
- ./nginx/nginx.conf:/etc/nginx/nginx.conf:ro
networks: [internal]
expose:
- "8080"
restart: unless-stopped
cloudflared:
image: cloudflare/cloudflared:latest
command: tunnel run
volumes:
- ./cloudflared/config.yml:/etc/cloudflared/config.yml:ro
restart: unless-stopped
networks: [internal]
networks:
internal:
driver: bridgenginx/nginx.conf
Code:
worker_processes 1;
events { worker_connections 1024; }
http {
proxy_headers_hash_bucket_size 128;
server {
listen 8080;
server_name _;
# Security headers
add_header X-Frame-Options DENY;
add_header X-Content-Type-Options nosniff;
add_header Referrer-Policy no-referrer;
add_header Content-Security-Policy "default-src 'self'";
location /health {
proxy_pass http://app:8000/health;
}
location / {
proxy_http_version 1.1;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto https;
proxy_set_header Connection "";
proxy_buffering off;
proxy_read_timeout 60s;
proxy_pass http://app:8000;
}
}
}cloudflared/config.yml
Code:
tunnel: <YOUR_TUNNEL_ID>
credentials-file: /etc/cloudflared/<YOUR_TUNNEL_ID>.json
ingress:
- hostname: secure.yourdomain.com
service: http://nginx:8080
originRequest:
noTLSVerify: true
- service: http_status:404app/Dockerfile
Code:
FROM python:3.11-sYou said:
what does nat and cgnat stand for and describe the traversal and can clouldflare solve my missing part.ChatGPT said:
Let’s decode this completely — because you’re 90% right about your architecture, but NAT and CGNAT are the invisible brick walls that block traffic before it ever reaches your Raspberry Pi.
What NAT and CGNAT mean
NAT — Network Address Translation
Your home router does this.
- You have many devices (Pi, laptop, phone) using private IPs like
192.168.1.12.
- Your ISP gives your router one public IP (e.g.,
99.44.33.22).
- NAT translates outgoing packets so they all look like they’re coming from that single public IP.
- When a reply comes back, it remembers which private device asked and forwards it there.
Problem: unsolicited inbound packets (like someone hitting https://yoursite.com) get dropped unless you port-forward them manually to the Pi.
CGNAT — Carrier-Grade NAT
Your ISP’s version of NAT for whole neighborhoods.
- Dozens or hundreds of customers share one public IP.
- You might be sitting behind another NAT layer you can’t control.
- Even if you port-forward in your own router, the ISP’s upstream NAT still blocks inbound requests.
Result: you can’t host anything that needs to accept inbound connections directly from the Internet.No amount of
A-records or DNS tweaking can punch through this.
NAT / CGNAT traversal
“Traversal” means getting packets through those NAT walls.Common methods:
- UPnP / NAT-PMP → automatically adds port-forward rules (works only for home NAT, not CGNAT)
- STUN/TURN/ICE → peer-to-peer hole punching (used by WebRTC)
- Reverse tunnel / reverse proxy → outbound connection from your device to a public relay that carries inbound traffic back down that pipe (best for your setup)
Why Cloudflare Tunnel fixes the missing piece
Cloudflare Tunnel (cloudflared) does exactly that last trick.- Your Pi makes an outbound HTTPS/WebSocket connection to Cloudflare’s edge network (this passes freely through NAT/CGNAT).
- Cloudflare keeps that connection open permanently.
- When someone visits
https://empirering.com, Cloudflare:- Terminates TLS
- Applies WAF, caching, Zero-Trust checks
- Sends the request down the existing tunnel to your Pi over that outbound link
- Your Pi replies, and the response goes back up the same path.
No ports opened No static IP needed Works through NAT and CGNAT TLS handled automaticallyFrom the Internet’s perspective, your Pi is invisible — Cloudflare’s edge is your public face.
Your corrected flow
Code:
[RING SCAN] → sends NFC payload to Cloudflare domain
↓
Cloudflare Edge (TLS + Zero Trust + rate limits)
↓
Cloudflare Tunnel (outbound persistent connection)
↓
Nginx on Raspberry Pi (reverse proxy to your app)
↓
Django/FastAPI app verifies:
- ring signature / nonce
- database lookup
- returns authorized response
↓
Response goes back through same tunnel
↓
Cloudflare Edge → HTTPS → browser/client
Bonus tip — verification path for the Empire Ring
Add these layers to make the scan secure and cloudflare-compatible:- Nonce challenge API (
/auth/nonce)
- Client requests a one-time nonce from your Pi through Cloudflare.
- Store it in Redis with 10-sec TTL.
- Ring signs the nonce (via HMAC key inside the ring chip or a derived key).
- Client submits the signature to
/auth/verify. - App validates HMAC + TTL + monotonic counter → issues JWT session.
Summary
| Concept | What it is | Problem | Solution |
|---|---|---|---|
| NAT | Router translating private→public | Blocks unsolicited inbound | Port-forward (if you control router) |
| CGNAT | ISP-level NAT | Blocks all inbound | Cannot port-forward |
| Traversal | Methods to get through | Complex & fragile | Use Cloudflare Tunnel |
| Cloudflare Tunnel | Outbound reverse tunnel | Works through any NAT | Perfect fit for Empire Node |
| Bonus | WAF, TLS, Zero-Trust | Adds security | Protects your Pi |
So yes — Cloudflare solves your missing part.
It becomes the secure middleman between the outside world and your bedroom-humming Raspberry Pi, letting your Empire Ring authentication system work from anywhere without fighting NAT or your ISP.
You said:
So there is no hardware to buy, no modification of my wifi account? All cloudflare?ChatGPT said:
Exactly — no new hardware and no modification to your Wi-Fi account or router.That’s the whole magic of Cloudflare Tunnel (aka Argo Tunnel /
cloudflared).Let’s unpack this clearly so you know exactly what happens and why you don’t need to buy or rewire anything.
The Key Principle
Cloudflare Tunnel flips the connection inside-out.Instead of the Internet trying to reach into your Pi (which fails because NAT/CGNAT block it),
your Pi reaches out to Cloudflare’s network and keeps a permanent, encrypted tunnel open.
That one outbound HTTPS/WebSocket connection can carry all inbound web traffic safely back down to your Pi.
Outbound traffic always works through your ISP’s firewall/NAT, so it needs no permission, no ports, no static IP, and no router access.
What you don’t need
| Old-school requirement | Cloudflare Tunnel eliminates it |
|---|---|
| Static public IP |  Not required |
| Router port-forwarding | Not required |
| DDNS service | Not required |
| Additional firewall rules | Not required |
| Hardware VPN appliance | Not required |
| Paid reverse proxy box | Not required |
- The Raspberry Pi itself (with your app running on any port, e.g.
8000)
- Internet access over Wi-Fi or Ethernet
- A free Cloudflare account managing your domain
What you do set up (software-only)
- Install Cloudflare’s agent
Code:sudo apt install cloudflared - Authenticate it
→ opens your browser → choose your domain → Cloudflare stores credentials locally.Code:cloudflared tunnel login - Create the tunnel
→ generates a JSON credential file (keep it safe).Code:cloudflared tunnel create empire-node - Configure it
Code:# /etc/cloudflared/config.yml tunnel: <YOUR_TUNNEL_ID> credentials-file: /etc/cloudflared/<YOUR_TUNNEL_ID>.json ingress: - hostname: pi.empirering.com service: http://localhost:8000 - service: http_status:404 - Run it
Code:cloudflared tunnel run empire-node - Add a DNS route
- In Cloudflare Dashboard → DNS tab
- Create a CNAME for
pi.empirering.com→ target:your-tunnel-id.cfargotunnel.com
pi.empirering.com→ hits Cloudflare’s edge
→ travels down the encrypted tunnel
→ lands on your Pi at
localhost:8000→ Nginx or Django serves it back up the same route.
Optional Upgrades
- Always-on:
sudo systemctl enable cloudflared && sudo systemctl start cloudflared - Zero-Trust Access (Cloudflare Access):
Require login, IP allowlists, device checks, or OTP before Cloudflare forwards a request. - Private DNS override:
You can even hide the hostname behind Access and only allow token-based entry (great for Empire Ring scans).
Bottom Line
| Category | Hardware Needed | Changes to Wi-Fi / ISP | Cost | Security |
|---|---|---|---|---|
| With port-forwarding | Router access | Yes | Free | Weak |
| With VPN hardware | Buy box | Maybe | $$ | Medium |
| With Cloudflare Tunnel | None | No changes | Free (1 tunnel) | Enterprise-grade |
In short:
That’s why it’s the perfect backbone for your Empire Ring → Cloudflare → Empire Node workflow.
Last edited:
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