VPN obfuscation
Updated 21 September 2026 · How we research
Obfuscation hides the fact that you are using a VPN. Encryption protects the contents of your traffic; obfuscation attacks the shape of it, so that deep packet inspection cannot classify the connection in the first place.
How VPN traffic gets identified
- Port. The crudest signal. Blocking UDP 500, 4500 and 1194 stops IKEv2 and default OpenVPN outright.
- Handshake fingerprint. WireGuard, OpenVPN and IKE each have a recognisable opening exchange that matches regardless of port.
- Packet timing and size. Tunnels produce distinctive patterns even when contents are opaque.
- Active probing. The network connects to your server itself to see whether it behaves like a VPN endpoint.
Common techniques
All obfuscation trades speed for resistance to detection.
| Technique | Idea | Limitation |
|---|---|---|
| Run on port 443 | Use the port every network must allow | Defeats port blocking only; DPI still sees the handshake |
| TLS wrapping | Put the tunnel inside a genuine TLS session | Adds overhead and often forces TCP |
| Obfuscation layers | Scramble the handshake so it matches no known signature | Vulnerable to active probing if the server answers unusually |
| Proprietary transports | Vendor-specific designs such as ZoogVPN's Shadow and ZoogTLS | No public specification, so effectiveness cannot be independently assessed |
Nothing here is guaranteed
Censorship systems are actively maintained and adapt. A transport that works today may be detected next month. Treat any provider's claim of guaranteed access to a specific restricted network as unverifiable — including claims made in vendor marketing.
ZoogVPN's options
ZoogVPN publishes two proprietary transports aimed at restricted networks: Shadow, listed for Windows, macOS, iOS and Android, and ZoogTLS, listed for Windows only. Both are described by the vendor as moderate speed, which is consistent with the overhead obfuscation normally carries.
Legal and personal risk
Rules on circumventing network restrictions differ sharply between countries and can carry serious consequences. Understand your own situation before relying on any of this. Nothing on this page is legal advice.