VPNInfobaseUnderstanding how a VPN works helps you use it more effectively and choose the right provider. This guide explains the process from connection to encryption. No technical background required.
The VPN tunnel
When you connect to a VPN, your device and the VPN server establish an encrypted tunnel. All data passing through is wrapped in layers of encryption that only your device and the server can decode. Think of it as a private underground pipe running beneath the open internet; everything inside is invisible to anyone outside.
IP masking
Your IP address reveals your device and approximate location. When you connect through a VPN server in a different country, every website sees that server’s IP instead of yours. You appear to be browsing from wherever the server is located, useful for geo-restricted content and preventing location-based advertising.
VPN protocols
A protocol is the set of rules a VPN uses to build the tunnel. WireGuard is a newer, deliberately compact protocol. OpenVPN is the long-established one and can be set to run over TCP port 443, which looks like ordinary web traffic and is harder to block. IKEv2 copes well with a phone switching between WiFi and mobile data. For how WireGuard and OpenVPN compare, see WireGuard vs OpenVPN.
DNS protection
DNS translates domain names into IP addresses. Without VPN DNS routing, queries go to your ISP’s servers even when the VPN is connected, exposing every domain you visit. A VPN that handles DNS properly sends those queries through the tunnel too. Run a DNS leak test after connecting to confirm it.
What a kill switch does and which VPNs have one
A kill switch is a VPN setting that is easy to miss, and some apps ship with it off.
What a kill switch does
If your VPN connection drops unexpectedly, a kill switch instantly blocks all internet traffic until it reconnects. Without it, your device falls back to your real IP, exposing your location and identity to every site you were connected to.
Why connections drop
Server overload, routing changes, switching from WiFi to mobile data, brief network interruptions, or ISP interference in countries that actively try to block VPN traffic.
System-level vs app-level
A system-level kill switch blocks all traffic when the VPN drops. An app-level kill switch lets you target specific applications only, so a torrent client is cut off while a video call continues. Which providers offer which kind is set out in each VPN review.
Which VPNs include a kill switch
Support differs by provider and by platform, so check the provider’s own documentation for your device. Always confirm the switch is enabled in the VPN app settings.
How VPN encryption works in detail
Encryption is the core technology that makes a VPN useful. The steps below follow a connection from key exchange to the cipher in use.
What encryption is
Encryption transforms readable data into scrambled ciphertext readable only by someone with the correct decryption key. Only your device and the VPN server hold the key.
AES-256: the standard
AES-256 is a widely used symmetric cipher, and many VPNs use it in GCM mode. No practical brute-force attack on it is known.
The handshake
Before encrypting your session, your device and the server agree on keys using asymmetric cryptography, which lets two parties agree on a shared secret over an open network. The session then switches to a symmetric cipher such as AES, which is much faster.
Perfect Forward Secrecy
With forward secrecy, a fresh session key is generated for each session, so a key compromised later does not expose recorded earlier sessions.
WireGuard’s approach
WireGuard uses a fixed set of modern primitives rather than letting users choose: Curve25519, ChaCha20, Poly1305 and BLAKE2, within the Noise protocol framework, as listed on wireguard.com.
Post-quantum encryption
Some providers are adding post-quantum key exchange to guard recorded traffic against future quantum computers. Whether a given provider has done so changes often, so check its own announcements.
What a no-logs policy means
Every VPN claims a no-logs policy. These sections cover what the claim means, why it matters, and how to tell whether a provider can back it up.
What no-logs actually means
A strict no-logs policy means the provider says it does not store records of your browsing activity, real IP address, connection timestamps, or data transferred, so there would be nothing to hand over if asked.
What some VPNs log even with the claim
Some providers state in their policies that they keep connection times, the server used, or total bandwidth, described as operational or aggregate data. Read the policy to see exactly what is kept.
Why independent audits are the only real proof
Any company can publish a privacy policy. Only a third-party audit of actual server infrastructure verifies it. Which providers have been audited, by whom and how recently is recorded in the audit tracker, taken from each vendor’s own pages and the auditors’ reports.
The real-world test
Mullvad reports that Swedish police visited its Gothenburg office with a search warrant to seize customer data, and says none existed and the police left without taking anything. That is Mullvad’s account of the event, and one such case does not prove a policy; the incidents timeline lists it with its source.
Jurisdiction matters alongside the policy
Providers based in places such as Panama, the British Virgin Islands and Switzerland say their local law does not require them to keep user data, while the US, UK and EU members can legally compel providers to retain and hand over data. Check the specifics for any provider in VPN jurisdiction explained.
For which providers have actually had a no-logs audit, by whom and whether the report is public, see the VPN audit tracker. For cases where logging claims met police or attackers, see the incidents timeline.
How the country a provider is based in relates to what authorities can compel is in VPN jurisdiction explained.
Split tunneling
Split tunneling lets you choose which apps use the VPN and which connect directly, targeted privacy without affecting everything on your device.
What split tunneling does
Instead of routing all traffic through the VPN, split tunneling creates exceptions. You can send your browser and torrent client through the VPN while letting your video calls, banking app, and local devices connect directly. This gives targeted privacy without applying it where unnecessary.
When to use it
Access your local bank while streaming from another country. Game with low latency while keeping browser traffic encrypted. Access home network devices like a printer while protecting other traffic. Exclude high-bandwidth apps that do not need VPN coverage to improve overall speed.
Which VPNs support split tunneling
Support varies by provider and by operating system, and some providers use their own name for the feature. Check the provider’s help pages for your platform before relying on it.
See also split tunneling in a VPN for what changes when an app skips the tunnel.