XTLS_Xray-docs-next/docs/en/config/outbounds/loopback.md

Loopback

Loopback is a loopback outbound used to send traffic back to routing for further processing without leaving the core.

OutboundConfigurationObject

OutboundConfigurationObject corresponds to the settings item in OutboundObject.

{
  "outbounds": [
    {
      // ...
      "protocol": "loopback",
      // [!code focus:3]
      "settings": {
        "inboundTag": "TagUseAsInbound"
      }
    }
  ]
}

inboundTag: string

The inbound tag used when re-entering routing.

This tag can be used as inboundTag in routing, indicating that data from this outbound will re-enter routing with this tag and be processed again by the corresponding rules.

::: tip Uses

• In places where only an outbound can be specified and balancerTag cannot be written directly, Loopback lets you use a balancer indirectly.
  For example, proxySettings and dialerProxy in chained proxies, and fallbackTag in load balancing.
• After traffic has already been routed once, it can be further subdivided using more conditions.
  For example, TCP traffic and UDP traffic split by the same set of routing rules can be sent to different outbounds.

:::