Obfuscation
Disguising VPN traffic so it resembles ordinary encrypted web traffic to a system inspecting the connection.
Glossary
Deep packet inspection
Also called: DPI
What is Deep packet inspection?
Deep packet inspection is network equipment that examines the structure of traffic rather than only its destination address. It is what separates a network that blocks a list of sites from one that detects and blocks the tool you use to reach them.
Why it matters
It is what separates a network that blocks a list of sites from one that detects and blocks the tool you use to reach them.
What most explanations leave out
DPI cannot read an encrypted payload, but "it only sees shape" understates it. Its first tools are the cleartext fields left inside otherwise-encrypted flows — the SNI in a TLS ClientHello, plaintext DNS, and the fixed protocol magic that identifies OpenVPN or WireGuard — before it falls back to packet sizes and timing. That is why obfuscation has to change the fingerprint rather than add encryption on top.
Related terms
SNI
The field in a TLS handshake that names the site being requested, historically sent unencrypted even over HTTPS.
Questions
- What is Deep packet inspection?
- Network equipment that examines the structure of traffic rather than only its destination address.
- Why does Deep packet inspection matter when choosing a VPN?
- It is what separates a network that blocks a list of sites from one that detects and blocks the tool you use to reach them.
- What do most explanations of Deep packet inspection leave out?
- DPI cannot read an encrypted payload, but "it only sees shape" understates it. Its first tools are the cleartext fields left inside otherwise-encrypted flows — the SNI in a TLS ClientHello, plaintext DNS, and the fixed protocol magic that identifies OpenVPN or WireGuard — before it falls back to packet sizes and timing. That is why obfuscation has to change the fingerprint rather than add encryption on top.
Terms are defined here because they appear in our scoring rubric or in provider reviews, not to fill a glossary.