Glossary · 61 terms

Proxy & VPN glossary

Every term with a one-line definition, deeper explanation, and related-term links. Jump by letter, search, or browse by category below.

19 letters populated · 61 terms total

A2 terms

Anonymous proxyCore

On proxy lists, an anonymous proxy is one that does not pass your real IP address to the site, though it may still reveal that a proxy is in use.

ASN (Autonomous System Number)Network

An ASN (autonomous system number) is the ID of one independently run network on the internet, such as an ISP, a cloud provider or a big company, used to route traffic between networks.

B2 terms

Bridge relayAdjacent

A Tor bridge is a Tor entry relay whose address is not published in the public relay list, so networks that block the known Tor relays cannot easily block it.

Browser extension proxyAdjacent

A browser extension proxy is an add-on installed in Chrome, Firefox or Edge that sends the browser's web traffic through a remote proxy server, switched on and off from the toolbar.

C2 terms

CDN (Content Delivery Network)Network

A CDN (content delivery network) is a company that runs servers in many cities and answers requests for a website from a location near the visitor instead of from the site's own server.

Cloudflare challengeWeb

A Cloudflare challenge is the 'Just a moment...' or 'Verifying...' screen a Cloudflare-protected site shows to check that a real browser is visiting before it serves the page.

D7 terms

Datacenter proxyCore

A data-centre proxy sends your traffic out from an IP address owned by a cloud or hosting company: fast and cheap, but easy for sites to recognise.

DNS is the system that turns a site name such as vimeo.com into the numeric IP address your device actually connects to.

DNS filteringCircumvention

DNS filtering blocks a website by making the address lookup fail or point somewhere else, so your browser never reaches the real server.

A DNS leak is when your device keeps asking its usual DNS server (often the ISP's) to look up site names while you think a VPN or proxy is handling your traffic, so the network still learns which sites you visit.

DNS-over-HTTPSWeb

DNS over HTTPS (DoH) sends your DNS lookups inside an encrypted HTTPS connection, so the network in between can neither read nor rewrite the answers.

DPI (Deep Packet Inspection)Web

Deep packet inspection (DPI) is network equipment that looks beyond a packet's addresses into its contents and patterns, to recognise and block or slow specific sites and apps.

DRM (Digital Rights Management)Circumvention

DRM (digital rights management) encrypts video or music so that only an approved player component can decrypt it, and only after the service's licence server agrees.

E3 terms

Edge serverNetwork

An edge server is a server placed close to users, at the 'edge' of a network, so requests are answered nearby instead of travelling to a distant central data centre.

Elite proxyCore

An elite proxy, also called high-anonymity or level 1, sends no header that reveals a proxy is in use, so the request looks like it came straight from the proxy's address.

Encrypted Client Hello (ECH) encrypts the opening message of an HTTPS connection, hiding the real site name (SNI) from the network; it replaced the earlier ESNI draft.

F1 term

Forward proxyCore

A forward proxy works for the user: it sends your requests out to the internet for you, so sites see the proxy instead of you.

G3 terms

Geo-blockCircumvention

A geo-block is a restriction set by the website or service itself: it checks where your connection appears to come from and refuses or changes what it shows.

GeoblockingCircumvention

Geoblocking is the general term for restricting access to online content based on the visitor's geographic location — includes streaming region locks, AI service region policies, and country-specific price differentiation.

GFW (Great Firewall of China)Circumvention

The Great Firewall is the filtering system on mainland China's international internet links that stops people inside China from reaching blocked foreign sites and apps.

H4 terms

HSTS (HTTP Strict Transport Security) is a header that tells browsers to use only HTTPS for a site for a set period, so a network cannot quietly downgrade you to unencrypted HTTP.

An HTTP proxy is a proxy that speaks the web's own protocol: it reads each request's address and headers and can filter, cache or log them.

HTTP/2 is the version of the web's request protocol that lets a browser send many requests at once over a single encrypted connection instead of queuing them.

HTTPS proxyCore

An HTTPS proxy is a proxy you connect to over an encrypted (TLS) link, so even the name of the site you ask it for is hidden from your local network.

I6 terms

IKEv2 (Internet Key Exchange version 2) is the standard protocol that sets up IPsec VPN connections; it is valued on phones because it can keep a VPN alive when the network changes.

Incognito modeAdjacent

Incognito mode (private browsing) is a browser window that forgets your history, cookies and form data when you close it; it does not hide your IP address or activity from websites or your network.

IP addressNetwork

An IP address is the number that identifies a device or server on a network, so packets know where to go; every website you visit sees one for you.

IP blockingCircumvention

IP blocking stops traffic to particular server addresses, so a site stays unreachable even when its name is looked up correctly.

An IPv6 leak is when a VPN protects your IPv4 traffic but your device still sends IPv6 traffic directly, exposing your real IPv6 address to websites.

ISP (Internet Service Provider)Network

An ISP (internet service provider) is the company that connects you to the internet, gives you a public IP address, routes your traffic and usually carries out national blocking orders.

K2 terms

Keyword filteringCircumvention

Keyword filtering blocks a connection when a banned word appears in traffic the network can read, such as a web address or a search term.

KominfoCircumvention

Kominfo was Indonesia's Ministry of Communication and Information Technology; renamed Komdigi in October 2024, it still runs the national website blocklist.

L1 term

Latency is the delay for data to travel from your device to a server and back, measured in milliseconds; it is why a page can feel slow on a fast connection.

M1 term

MITM (Man-in-the-Middle)Web

A man-in-the-middle (MITM) is anything that sits between you and a website and can read or change the traffic, whether as an attack, as company policy or as a service you chose.

O2 terms

ObfuscationAdjacent

Obfuscation means disguising a VPN or proxy connection so that network filters cannot recognise what kind of traffic it is and block it.

OpenVPN is an open-source VPN protocol and program, first released in 2001, that builds its encrypted tunnel with TLS and can run over either UDP or TCP.

P5 terms

PoP (Point of Presence)Network

A point of presence (PoP) is a physical site, usually a rack in a data centre, where a network has equipment and connects to other networks and to its users.

A port is a number from 0 to 65535 that tells a device which service a network connection is for, such as 443 for HTTPS or 53 for DNS.

Private browsingAdjacent

Private browsing is the generic name for a browser window that forgets your history, cookies and form data when you close it - Chrome calls it Incognito; it does not hide your IP address or activity from websites or your network.

A proxy is a server that makes network requests for you and passes the answers back, so the site you reach deals with the proxy instead of your device.

PTA (Pakistan Telecommunication Authority)Circumvention

The Pakistan Telecommunication Authority (PTA) is Pakistan's telecom regulator; it orders internet providers to block websites and apps, usually at the government's direction.

R3 terms

Residential proxyCore

A residential proxy sends your traffic out through an IP address that an ordinary home internet provider assigned to someone's connection.

Reverse proxyCore

A reverse proxy works for a website: it sits in front of the site's servers, takes every visitor's connection, and decides what reaches the real server.

RoskomnadzorCircumvention

Roskomnadzor is Russia's federal regulator for communications and media; it keeps the register of banned websites that Russian internet providers must block.

S5 terms

ScramjetAdjacent

Scramjet is an open-source web proxy from Mercury Workshop that intercepts and rewrites websites inside your own browser, using a service worker, rather than on a remote server.

SNI inspectionWeb

SNI inspection is a filtering technique: a firewall reads the site name from the start of an HTTPS connection and cuts or logs the connection if the name is on a list.

SOCKS proxyCore

A SOCKS proxy relays raw network connections for any app without understanding what is inside them; SOCKS5 can also carry UDP.

Split tunnelingVPN

Split tunneling is a VPN setting that sends only selected apps or destinations through the VPN while the rest of the device's traffic uses the normal connection.

A subnet is a block of consecutive IP addresses that share the same starting bits, written like 208.65.152.0/22, and routed or filtered as one unit.

T5 terms

ThroughputNetwork

Throughput is how much data actually reaches you per second, the real rate of a connection as opposed to the maximum (bandwidth) your plan advertises.

TLS handshakeWeb

The TLS handshake is the opening exchange of every HTTPS connection, in which browser and server agree on encryption keys and the server proves which site it is.

SNI (Server Name Indication) is the field at the start of an HTTPS connection where your browser names the site it wants, usually in readable text.

Tor is a free network and browser that sends your traffic through three volunteer-run relays, each adding a layer of encryption, so no single relay knows both who you are and what you are visiting.

Transparent proxyCore

A transparent proxy is one the network puts in your path without you setting it up; on proxy lists the same word means a proxy that passes your real IP along.

V3 terms

A VPN (virtual private network) is software that sends all of a device's network traffic through an encrypted connection to a provider's server, which then contacts websites on the device's behalf.

VPN kill switchVPN

A VPN kill switch is a setting that cuts a device's internet access whenever the VPN connection drops, so apps cannot fall back to the unprotected connection.

A VPN tunnel is the encrypted link between a device and a VPN server, made by wrapping each original packet inside a new packet addressed to the server.

W4 terms

A web proxy is a website that loads other websites for you inside your browser tab, with nothing to install and no settings to change.

A WebRTC leak is when a website uses the browser's built-in calling technology (WebRTC) to discover your real public IP address, even though your normal page traffic goes through a proxy or VPN.

WireGuard is an open-source VPN protocol that encrypts traffic with a small, fixed set of modern algorithms and runs only over UDP.

Wisp protocolAdjacent

Wisp is an open protocol that carries many TCP and UDP connections inside one WebSocket, so code running in a browser tab can reach network services a web page normally cannot open.

How this glossary is written

Every entry starts with a single-sentence definition that answers the "what is X" query directly. The longer body (200-300 words per term) adds context — how the concept relates to proxies, VPNs, and network filtering — plus links to 3-5 related terms so readers can navigate the topic graph.

This is the backbone for the rest of the site — every long-form page (how-tos, concept comparisons, cornerstones, blog) links into relevant glossary terms so you can drill down without leaving the flow.