zyrln

Zyrln

راهنمای فارسی

Censorship circumvention that routes traffic through Google's infrastructure — no typical VPN fingerprint, no dedicated exit IP that is easy to block on its own.

Downloads: GitHub Releases

Also: Cloudflare exit setup · Contributing

How it works

Many networks block sites by inspecting TLS (DPI / SNI). Zyrln uses two paths:

Google services (Gmail, Drive, Maps, etc.): Traffic goes straight to Google, but the TLS ClientHello is split into small fragments so middleboxes that rely on a clean SNI often fail to classify the connection. No server needed.

Everything else (Instagram, X, Telegram, …):

Your device → Zyrln → Google Apps Script → your exit relay → the real site

Your device's TLS connections go to Google's own IP ranges; only the encrypted Host header — invisible to DPI — actually points at your Apps Script deployment. From a censor's point of view, this traffic is indistinguishable from someone using Google Docs. Apps Script then forwards to your exit relay (VPS or Cloudflare), which opens the real destination.

Client relay/tunnel traffic must go through Apps Script (never point the app at the VPS/Worker URL). The exit is reached only from Google's side.

Google only (Gmail, Drive, Maps)

No server. No relay setup.

1. Download for your platform from Releases
2. Run the app — the GUI opens in your browser
   • Windows: double-click the .exe
   • Linux / macOS: run with -gui:
     bash复制

     ./zyrln-VERSION-linux-amd64 -gui          # Linux
     ./zyrln-VERSION-darwin-arm64 -gui         # macOS Apple Silicon
     ./zyrln-VERSION-darwin-amd64 -gui         # macOS Intel

3. Click the lightning bolt in the top bar to enable Direct Mode
4. Set your browser HTTP proxy to 127.0.0.1:8085

Direct Mode works for Google services that are SNI-filtered but not IP-blocked. YouTube streaming and Play Store downloads typically need the full relay. Behavior varies by ISP and location.

Full access (Instagram, Twitter, Telegram, …)

Relay chain setup takes about 15 minutes.

Follow the steps in order: the client generates your keys first, the exit relay needs one of them, and Apps Script needs the exit relay's URL plus both keys. Doing it in this order means you never have to backtrack and re-paste a value you didn't have yet.

What you need

Step 1 — Desktop app

1. Download from Releases
2. Run — GUI opens in the browser (Windows: .exe; Linux/macOS: -gui as above)
3. Security → generate and install the CA certificate (desktop only — needed for HTTPS relay via MITM)
4. Settings → Generate Key → copy the auth key for Apps Script

Browser proxy:

CA certificate (desktop relay only):

• Chrome/Edge: Settings → Privacy → Security → Manage certificates → Authorities → Import zyrln-ca.pem
• Firefox: Settings → Privacy & Security → Certificates → Authorities → Import

Step 2 — Exit relay

The exit fetches real websites. Pick one — Cloudflare is simpler and free; a VPS gives you more control over who can see your traffic's destination metadata.

Option A — Cloudflare Worker (free)

See Cloudflare Worker setup — deploy from relay/deploy/cloudflare/.

Option B — VPS

Linux VPS (amd64 or arm64), public IP, port 8787 open, SSH as user@host with sudo.

1. Download zyrln-VERSION-vps.zip from Releases and unzip
2. Run ./install-vps-relay.sh user@YOUR_VPS_IP
   Set ZYRLN_RELAY_KEY=secret or ZYRLN_RELAY_KEY=auto — same value as EXIT_RELAY_KEY in Apps Script
3. In Code.gs: EXIT_RELAY_URL = "http://YOUR_VPS_IP:8787/relay" and matching EXIT_RELAY_KEY

Check: curl -s http://YOUR_VPS_IP:8787/healthz → ok

Step 3 — Apps Script relay

Front door on Google's servers.

Two keys

Two separate, independent secrets — confusing them is the most common setup mistake. The app only uses key 1.

Key 2 uses the same name on VPS and Cloudflare (ZYRLN_RELAY_KEY). Same value in EXIT_RELAY_KEY (Code.gs) and ZYRLN_RELAY_KEY (exit). If the exit has no key, leave EXIT_RELAY_KEY empty in Code.gs.

App ──key 1──► Apps Script ──key 2──► Cloudflare or VPS

1. script.google.com → New project
2. Paste relay/deploy/apps-script/Code.gs
3. Edit constants — Cloudflare or VPS, not both:

Cloudflare:

const AUTH_KEY        = "your-key-from-step-1";
const EXIT_RELAY_URL  = "https://your-worker.your-subdomain.workers.dev";  // no /relay
const EXIT_TUNNEL_URL = "";
const EXIT_RELAY_KEY  = "your-exit-key";

VPS:

const AUTH_KEY        = "your-key-from-step-1";
const EXIT_RELAY_URL  = "http://YOUR_VPS_IP:8787/relay";
const EXIT_TUNNEL_URL = "http://YOUR_VPS_IP:8787/tunnel";
const EXIT_RELAY_KEY  = "your-exit-key";

1. Deploy → New deployment → Web app → Execute as Me → Access Anyone
2. Copy the URL: https://script.google.com/macros/s/AKfycb.../exec

Each Google account gets ~20,000 relay calls/day. Add multiple deployments (different accounts) comma-separated in the app for resilience.

Step 4 — Connect (desktop)

1. Click + to add a profile
2. Paste Apps Script URL and auth key
3. Save → Connect

Step 5 — Android

1. Install APK from Releases
2. Add config:
   • Import Config from Clipboard (JSON from desktop Tools → Mobile Export, or from another phone's share icon), or
   • + and enter URL + key manually
3. Tap the config → Connect → allow VPN permission
4. Optional: Split tunnel — route only selected apps through Zyrln (disconnect VPN to change settings)
5. Share a config: tap the share icon on a config row — JSON copies to clipboard

Building from source

Requires Go 1.25+.

make desktop              # local ./zyrln
make desktop-release      # dist/ for Linux, Windows, macOS
make desktop-linux|windows|macos
make keystore             # once — Android signing key
make android              # signed release APK
make proxy                # run proxy from source (needs CA)
make test
make vps-relay-bundle     # → dist/zyrln-VERSION-vps.zip

See docs/contributing.md for project layout and developer notes.

Troubleshooting

Relay chain not connecting (full access setup)

Check in order:

1. Apps Script deployment live, with access set to "Anyone"?
2. EXIT_RELAY_KEY in Apps Script exactly matches ZYRLN_RELAY_KEY on your VPS? (Cloudflare doesn't use this key.)
3. VPS relay running and firewall port open? curl -s http://YOUR_VPS_IP:8787/healthz → ok
4. Redeployed Apps Script after your last constant change? (Deploy → Manage deployments → pencil icon → New version → Deploy)

Nothing loads through the proxy

• Proxy running? (green indicator in GUI)
• Browser proxy set to 127.0.0.1:8085
• Run diagnostics (play button in Tools)

HTTPS SSL errors (desktop only)

• CA not installed or not trusted — re-import certs/zyrln-ca.pem

Apps Script quota exceeded

• Add deployments from other Google accounts; comma-separate URLs in the app

YouTube works but Instagram doesn't

• Instagram is IP-blocked — needs full relay chain
• Confirm VPS/Cloudflare exit is running

X / Discord / ChatGPT fail on Cloudflare Worker exit

• Worker can't reach other Cloudflare-hosted sites — use a VPS exit. See docs/cloudflare-setup.md.

Security

• Deploy your own Apps Script and generate your own auth key
• Never commit config.env, certs/, or keys
• Google and your exit provider see metadata (timing, volume), not encrypted payload content on the tunnel path
• Rotate keys if leaked
• Keep certs/zyrln-ca-key.pem on your device only (desktop)

Credits

Domain-fronting: denuitt1/mhr-cfw. TLS fragmentation: GFW-knocker.

License: MIT — LICENSE.