Reverse Proxy

Reverse proxy is an additional feature of V2Ray that allows forwarding server-side traffic to the client, effectively enabling reverse traffic forwarding.

The basic working principle of reverse proxy is as follows:

• Suppose there is a web server on host A that has no public IP address and cannot be accessed directly from the internet. There is another host B that can be accessed from the public internet. We need to use B as an entry point to forward traffic from B to A.
• Configure a V2Ray instance called bridge on host A, and another V2Ray instance called portal on host B.
• bridge actively establishes connections to portal with a configurable destination address. portal receives two types of connections: ones from bridge and ones from public internet users. portal automatically merges these two types of connections, allowing bridge to receive public internet traffic.
• After receiving public traffic, bridge forwards it unchanged to the web server on host A. This step requires routing cooperation.
• bridge performs dynamic load balancing based on traffic volume.

ReverseObject

ReverseObject corresponds to the reverse entry in the configuration file.

{
    "bridges": [
        {
            "tag": "bridge",
            "domain": "test.v2fly.org"
        }
    ],
    "portals": [
        {
            "tag": "portal",
            "domain": "test.v2fly.org"
        }
    ]
}

bridges: [BridgeObject]

An array where each item represents a bridge. Each bridge configuration is a BridgeObject.

portals: [PortalObject]

An array where each item represents a portal. Each portal configuration is a PortalObject.

BridgeObject

{
    "tag": "bridge",
    "domain": "test.v2fly.org"
}

tag: string

An identifier that all connections from the bridge will carry. This can be used in routing with inboundTag for identification.

domain: string

A domain name used for connections from bridge to portal. This domain name is only used for communication between bridge and portal and doesn't need to actually exist.

PortalObject

{
    "tag": "portal",
    "domain": "test.v2fly.org"
}

tag: string

The portal identifier. Used in routing with outboundTag to forward traffic to this portal.

domain: string

A domain name. When portal receives traffic, if the destination domain matches this domain, portal considers it a communication connection from bridge. Other traffic is treated as traffic to be forwarded. The portal's job is to identify and merge these two types of connections.

Complete Configuration Examples

A bridge typically needs two outbound proxies: one for connecting to the portal and another for sending actual traffic. This means you need to use routing to distinguish between these two types of traffic.

Reverse proxy configuration:

{
    "bridges": [
        {
            "tag": "bridge",
            "domain": "test.v2fly.org"
        }
    ]
}

Outbound proxy:

{
    "tag": "out",
    "protocol": "freedom",
    "settings": {
        "redirect": "127.0.0.1:80" // Forward all traffic to web server
    }
},
{
    "protocol": "vmess",
    "settings": {
        "vnext": [
            {
                "address": "portal's IP address",
                "port": 1024,
                "users": [
                    {
                        "id": "27848739-7e62-4138-9fd3-098a63964b6b"
                    }
                ]
            }
        ]
    },
    "tag": "interconn"
}

Routing configuration:

"routing": {
    "rules": [
        {
            "type": "field",
            "inboundTag": [
                "bridge"
            ],
            "domain": [
                "full:test.v2fly.org"
            ],
            "outboundTag": "interconn"
        },
        {
            "type": "field",
            "inboundTag": [
                "bridge"
            ],
            "outboundTag": "out"
        }
    ]
}

A portal typically needs two inbound proxies: one for receiving connections from bridge and another for receiving actual traffic. You also need routing to distinguish between these two types of traffic.

Reverse proxy configuration:

{
    "portals": [
        {
            "tag": "portal",
            "domain": "test.v2fly.org" // Must match bridge configuration
        }
    ]
}

Inbound proxy:

{
    "tag": "external",
    "port": 80, // Open port 80 for external HTTP access
    "protocol": "dokodemo-door",
    "settings": {
        "address": "127.0.0.1",
        "port": 80,
        "network": "tcp"
    }
},
{
    "port": 1024, // For receiving bridge connections
    "tag": "interconn",
    "protocol": "vmess",
    "settings": {
        "clients": [
            {
                "id": "27848739-7e62-4138-9fd3-098a63964b6b"
            }
        ]
    }
}

Routing configuration:

"routing": {
    "rules": [
        {
            "type": "field",
            "inboundTag": [
                "external"
            ],
            "outboundTag": "portal"
        },
        {
            "type": "field",
            "inboundTag": [
                "interconn"
            ],
            "outboundTag": "portal"
        }
    ]
}