V2Ray Glossary: Protocols, Cores & Routing Rules

Connection Settings

Protocols & Transports

The protocol defines how communication works, the transport carries the data, and the security layer protects the connection. Configure each separately; a node name alone is not enough to confirm compatibility.

VMess: Protocols & TransportsA proxy protocol in the V2Ray ecosystem that uses a user ID for authentication. The client and server must use compatible settings. After importing a configuration, check not only the protocol but also the address, port, user ID, transport and security layer. A significantly incorrect system clock can also affect authentication, so check time synchronization when a connection fails instead of repeatedly switching servers.

VLESS: Protocols & TransportsA lightweight proxy protocol that does not encrypt traffic on its own. In practice, it is usually paired with a security layer such as TLS or REALITY. VLESS is not another name for VMess; both ends must use the same protocol type. The core in use must also support the configured flow control, security layer and transport. A successful import alone does not mean the connection will work.

Trojan: Protocols & TransportsA proxy protocol that typically establishes a secure connection over TLS and authenticates users with a password. The server address, password, server name and certificate validation settings all affect the connection; a mismatch in any one can cause the handshake to fail. When troubleshooting certificate errors, check the name, validity period and system clock. Disabling certificate validation is not a routine fix.

REALITY: Protocols & TransportsA transport security scheme in the Xray ecosystem, often used with VLESS. It is not a proxy protocol that can replace VLESS on its own. Configuration typically includes parameters such as the server public key, server name and short ID; use the values provided by the server and check compatibility with your client version. Preserve all parameters when editing manually. Missing security settings can leave the server port reachable while actual requests fail.

Transport: Protocols & TransportsThe connection method used to carry proxy protocol data. Common types include TCP, WebSocket and gRPC. Transport is separate from proxy protocols such as VMess and VLESS, and cannot replace a security layer such as TLS. WebSocket paths and gRPC service names must match the server settings; changing them at random will not make a connection faster.

Project Relationships

Cores & Ecosystem

First distinguish the project, execution core and graphical interface, then check which one supports the setting in question. Updating a client is not the same as updating its core.

Project V: Cores & EcosystemA collective term for projects focused on networking tools, with V2Ray as a key component. In everyday use, “V2Ray” can mean the core program or the broader ecosystem of clients and configurations. Use context to tell which meaning a guide intends. Project V is not a subscription service, and installing a graphical client does not automatically provide server configurations.

V2Fly: Cores & EcosystemA community project that maintains the V2Ray core implementation and related documentation, handling low-level tasks such as protocol processing and network connections. v2flyNG is an Android client option based on this core ecosystem. Protocol, transport and configuration support can vary by version, so check the capabilities of the core in use rather than copying examples for another core without changes.

Xray: Cores & EcosystemA proxy core project that grew out of the V2Ray ecosystem. v2rayNG uses the Xray core. Xray and V2Fly share technical roots, but their features and configuration details are not identical; check that settings such as REALITY are supported. A protocol option appearing in the graphical interface does not guarantee that every installed core can handle every combination.

Client and Core: Cores & EcosystemThe client manages subscriptions, server lists, settings and system integration; the core handles protocols, connections and routing. v2rayN is the name of a graphical client, not a core project. If startup fails, first determine whether the interface will not open, the core process will not start, or the core starts but requests fail. Then check the relevant logs.

Configuration Sources

Subscriptions & Nodes

A subscription retrieves configurations, a node is an individual server configuration, and groups organize the list. Assess the number of entries separately from connection quality.

Subscription: Subscriptions & NodesA URL or content source for retrieving server configurations in bulk. When the client updates a subscription, it refreshes the server list from that source. Subscription URLs may contain access credentials, so treat them like account information and redact them from screenshots or logs before sharing. A successful update means the configurations were retrieved and parsed; it does not prove that every node can currently connect.

Node: Subscriptions & NodesUsually, a server configuration that a client can use to establish a proxy connection, including an address, port, authentication details, protocol and transport settings. A node's display name does not confirm its server location or service quality. In v2rayN, distinguish selecting a row from setting it as the active server. Check the active indicator and connection logs in your version to confirm which configuration is actually in use.

Subscription Group: Subscriptions & NodesA way to organize server lists by configuration source or intended use, helping separate subscriptions from manually imported entries. In v2rayN, subscription groups manage sources, while group labels filter the current list. A group is not traffic routing, and switching list filters does not automatically change the active server. If the list appears empty after an update, check the filter first.

Latency: Subscriptions & NodesThe time from sending a request to receiving a response under a specific test method, usually used to compare connection responsiveness at that moment. TCP connectivity tests, real connection tests and in-app response times measure different things, so their results are not directly comparable. Lower latency does not mean higher download bandwidth or guarantee the same performance for video, file transfers or every website.

How-to: Import a Subscription →

Traffic Flow

Routing & DNS

Routing determines which outbound a connection uses; DNS determines how a domain is resolved. They can affect each other, but changing one does not replace the other.

Routing Rule: Routing & DNSA rule that selects an outbound route for a connection based on its domain, destination address, port or other criteria. Common outbounds are direct, proxy and block. Rules are usually checked in order; unmatched connections follow the default behavior. When adding a rule, first check its matching conditions, then see whether a broader rule earlier in the list takes precedence. Looking at rule names without checking their order can lead to the wrong conclusion about where traffic goes.

GeoIP: Routing & DNSRule data that matches destinations against IP address ranges. Common references include geoip:cn and geoip:private. The latter usually matches private or reserved address ranges; the exact set depends on the data file in use. GeoIP does not resolve domain names to addresses. Whether a domain rule triggers an IP match also depends on the core's DNS strategy and routing settings.

GeoSite: Routing & DNSRule data that matches destinations against domain collections. geosite:cn is a common reference. It matches a collection of domains; it does not measure the physical location of each server or replace all IP rules. Category names, coverage and available tags depend on the data file in use. If a category cannot be found, check the data source, update status and spelling of the reference.

Traffic Routing: Routing & DNSRoutes different connections through a direct, proxy or blocked outbound according to rules, rather than handling all traffic the same way. In v2rayN, “Bypass mainland China (Whitelist),” “Blacklist” and “Global” are common routing preset names; check the current rules to see what each one does. Even a global preset only affects connections handled by the relevant core; it does not mean every app on the device is captured.

DNS: Routing & DNSA system that resolves domain names into network addresses and other records that apps need to find a service. The operating system, browser and proxy core can each have their own DNS settings and caches, so changing the core's DNS may not change the resolution path used by every app. When troubleshooting, check which component makes the query, where it is sent and how the result affects subsequent routing.

FakeDNS: Routing & DNSAssigns a temporary virtual address to a domain and stores the mapping, then restores the domain when a connection arrives so routing and outbound handling can use it. A virtual address is not the destination server's real address and should not be used independently of the corresponding core. DNS requests and subsequent connections must follow the matching handling path. After changing or disabling the setting, old cache entries may remain; clear them or rebuild the connection as directed by the client.

DNS Leak: Routing & DNSWhen domain queries do not follow the intended resolution path—for example, a query expected to use the proxy path is instead sent by an app to the local network. Seeing a particular DNS provider in a test is not enough on its own to confirm a problem; compare the result with your intended routing and DNS setup. Check browser secure DNS, system resolution settings, core DNS and TUN capture scope to distinguish deliberate local resolution from unintended routing around the expected path.

Interface and Controls

Client Features

First check how traffic enters the client, then how the core handles it. System proxy, TUN and routing presets are settings at different layers.

TUN Mode: Client FeaturesUses a virtual network interface to capture IP traffic covered by system routing rules, allowing apps that ignore system proxy settings to enter the proxy handling path. In v2rayN, “Enable Tun Mode” involves the virtual interface, system permissions, routing and DNS settings. Make sure ordinary proxy connections work before enabling it. TUN does not mean all traffic must use the proxy; the actual route depends on the capture scope and core rules.

System Proxy: Client FeaturesA set of proxy settings provided by the operating system, usually pointing to a local proxy listener opened by the client. Whether an app uses these settings depends on the app; browsers, command-line tools and other apps may use different proxy mechanisms. A running client core does not mean the system proxy is enabled. If the client exits without clearing stale settings, apps that rely on the system proxy may lose access.

Real Connection Latency: Client FeaturesThe time taken to send a request to a test destination through a specified proxy configuration. Depending on the client, this may include connection setup, the security handshake and the destination's response. Compared with checking whether a port is reachable, it gives a better indication of whether that proxy request can complete. A timeout does not necessarily mean the server is offline; the test address, DNS resolution or destination restrictions may be responsible. Check the logs and test another destination.

Local Listening Port: Client FeaturesThe local entry point where the client accepts proxy requests from apps. It is not the remote server port in a node configuration. If another process is using the port, the listener may fail to start; switching remote nodes usually will not help. After changing the local port, update apps where the proxy address was entered manually. Also check whether the listener is restricted to the local device to avoid exposing it more widely than intended.

Switching Between Cores: Client FeaturesThe ability to choose an execution engine from multiple cores supported by the client; it does not mean both cores process the same connection at once. Whether switching is available and which cores can be selected depend on the client version and configuration type. Before switching, check that the target core supports the protocol, transport, security layer, DNS and routing rules. Use this feature to address a specific compatibility issue, not as a general speed boost.

Keep reading: Getting Started · Advanced Setup · Troubleshooting