VPN Glossary
A plain-English guide to every VPN term you'll ever encounter.
A
AES-256
Advanced Encryption Standard with 256-bit key length. The gold standard of symmetric encryption, used by governments and militaries worldwide. Virtually unbreakable with current computing power.
D
DNS Leak
When DNS (Domain Name System) requests bypass the VPN tunnel and expose your browsing activity to your ISP or DNS provider. A good VPN prevents DNS leaks by routing all DNS requests through its own servers.
Double VPN
Also called multi-hop, this routes your traffic through two separate VPN servers, adding an extra layer of encryption. Slower than single-hop but significantly more secure.
I
IKEv2/IPSec
Internet Key Exchange version 2 paired with IPSec. A fast and stable VPN protocol, especially good for mobile devices due to its ability to reconnect quickly when switching networks.
IP Address
A unique numerical label assigned to every device on a network. Your IP address reveals your approximate location and ISP. A VPN replaces your real IP with the server's IP.
ISP
Internet Service Provider — the company that provides your internet connection (e.g., Comcast, AT&T, BT). Your ISP can see and log all your unencrypted internet activity.
K
Kill Switch
A safety feature that automatically cuts your internet connection if the VPN drops. This prevents your real IP from being exposed during unexpected disconnections.
L
L2TP/IPSec
Layer 2 Tunneling Protocol combined with IPSec. An older protocol considered less secure than modern alternatives like WireGuard or OpenVPN. Avoid if possible.
Lightway
ExpressVPN's proprietary VPN protocol, built for speed and security. It uses wolfSSL and is open-source, offering performance comparable to WireGuard.
Logs/Logging Policy
The record a VPN keeps of user activity. A 'no-logs' policy means the VPN doesn't store records of what you do online. Look for VPNs with independently audited no-logs policies.
N
NordLynx
NordVPN's proprietary protocol built on WireGuard. It adds a double NAT system to address WireGuard's privacy limitations while retaining its speed advantages.
O
Obfuscation
A technique that disguises VPN traffic as regular HTTPS traffic, making it harder for ISPs and firewalls to detect and block VPN usage. Essential for use in countries like China.
OpenVPN
An open-source VPN protocol known for its strong security and flexibility. It's highly configurable and widely audited, making it the industry standard, though slightly slower than newer protocols.
P
P2P
Peer-to-peer file sharing (e.g., torrenting). Many VPNs offer dedicated P2P servers optimized for file sharing while maintaining privacy and speed.
Port Forwarding
A technique that allows external devices to connect to a specific service on your network. Some VPNs support port forwarding, which can improve P2P download speeds.
R
RAM-Only Servers
VPN servers that run entirely on volatile RAM instead of hard drives, meaning all data is wiped when the server is powered off. Used by ExpressVPN (TrustedServer) for enhanced security.
S
Secure Core
Proton VPN's implementation of multi-hop routing, sending traffic through servers in privacy-friendly countries (Switzerland, Iceland) before reaching the exit server.
SOCKS5 Proxy
A type of internet proxy that routes traffic without encryption. Faster than VPN but less secure. Often paired with VPN for torrenting to get the best of both worlds.
Split Tunneling
A feature allowing you to choose which apps or websites use the VPN connection and which use your regular internet connection. Useful for accessing local services while protecting other traffic.
SSL/TLS
Secure Sockets Layer / Transport Layer Security. Encryption protocols that secure data in transit over the internet. Some VPN protocols use TLS for the control channel.
T
Tor Over VPN
Connecting to the Tor anonymity network through a VPN. Provides maximum privacy but is very slow. Supported by NordVPN and Proton VPN.
Tunneling Protocol
The method a VPN uses to encapsulate and transmit your data. Common protocols include WireGuard, OpenVPN, IKEv2, and L2TP. Each has different speed and security characteristics.
V
VPN
Virtual Private Network — a service that encrypts your internet traffic and routes it through a server in a location of your choosing, hiding your IP address and protecting your data.
W
WebRTC Leak
A browser vulnerability that can expose your real IP address even when using a VPN. Modern VPN browser extensions block WebRTC leaks. You can test for it at browserleaks.com.
WireGuard
A modern VPN protocol with a lean codebase (~4,000 lines vs OpenVPN's 400,000+). Offers significantly faster speeds and simpler auditing, making it the preferred protocol for most modern VPNs.