Wiki: what is it

Explains every concept that appears in the guide. Each entry has the same structure: one-line explanation → an analogy → where it sits in this setup → common misconceptions.

Short on time? In the guide, hover over any dotted-underlined word for a one-line explanation, and click it to land here.

Networking basics

• IP addressAn IP address is a device's street address on the network. Data packets use it to know where to go and where they came from.
• Domain names and DNSDNS translates easy-to-remember site names (domains) into IP addresses.
• DNS leakWhen you visit a site, its name gets looked up by your local network's DNS, so others can tell where you are and what you visit. That is a DNS leak.
• Proxy, VPN, node, "airport"A proxy is a middleman that visits websites for you; a node is your tunnel to the proxy server; an "airport" (机场) is a shared proxy service used by many people; a VPN is a related technology that joins your whole device to another network.
• PortsPorts number the different services on one server, so one IP can run many services at once.
• TCP and UDPTCP and UDP are two ways to send data: TCP is reliable and ordered; UDP is fast but does not guarantee delivery.
• WebRTCWebRTC is the browser's built-in real-time audio/video feature behind web video meetings and voice calls. It reports your IP to the outside over UDP.

Security

• HTTPS and certificatesHTTPS is encrypted web access; a certificate is an electronic document proving a site is who it claims to be.
• SSH, public and private keysSSH is how you log in to a server remotely and run commands on it. Logging in with keys is far safer than with a password.
• FirewallA firewall decides which ports may accept connections from outside and rejects everything else.

Server

• VPS and data-center routesA VPS is a virtual computer rented in a data center; the route is the network path from your home to that data center.
• Why it is slower in the eveningFrom 8 to 11 pm, routes from China abroad are most congested; packet loss rises and speed drops noticeably.
• BBRBBR is a smarter way of controlling sending speed that runs steadier and faster on lossy routes.
• Traffic and bandwidthTraffic is how much data you can transfer per month (for example 1 TB); bandwidth is how fast it can flow at any moment (for example 1 Gbps).

Parts of this setup

• Xray, VLESS, RealityXray is the program on the server that actually forwards traffic; VLESS is the protocol it speaks with your app; Reality is a disguise that makes a node look like an ordinary HTTPS website.
• 3x-ui3x-ui is the web panel that manages Xray: nodes, users, traffic stats and subscriptions.
• SubscriptionA subscription is a URL. Your app opens it to fetch the nodes and routing rules, and refreshes it periodically.
• Rule-based routingRouting decides how each site is reached by rules: Chinese sites directly; foreign sites and AI tools through your server.
• System proxy vs TUNA system proxy only takes over web traffic from apps that respect system settings (mainly browsers); TUN mode takes over all traffic from every app, including UDP.
• CLIProxyAPICLIProxyAPI is an open-source program on your server that turns your own AI accounts (such as ChatGPT or Claude) into a standard API for all kinds of AI tools.

AI and accounts

• IP reputation and risk controlWebsites score visitors' IPs: home broadband or data center, history of abuse, known proxy or not. Low scores can mean extra verification or restrictions.
• Time zone and browser fingerprintBesides the IP, websites also look at your time zone, language, OS, screen, fonts and more — together a "browser fingerprint".
• API and API keysAn API is an interface programs use to call each other; an API key is the credential shown with each call — whoever has it can use it.