XTLS/Xray-core · error

udp requires hysteria udp transport

Error message

udp requires hysteria udp transport

What it means

Error "udp requires hysteria udp transport" thrown in XTLS/Xray-core.

Source

Thrown at proxy/hysteria/client.go:127

			if !ok {
				return errors.New(msg)
			}
			return buf.Copy(buf.NewReader(conn), link.Writer, buf.UpdateActivity(timer))
		}

		responseDoneAndCloseWriter := task.OnSuccess(responseDone, task.Close(link.Writer))
		if err := task.Run(ctx, requestDone, responseDoneAndCloseWriter); err != nil {
			return errors.New("connection ends").Base(err)
		}

		return nil
	}

	if target.Network == net.Network_UDP {
		iConn := stat.TryUnwrapStatsConn(conn)
		_, ok := iConn.(*hysteria.InterConn)
		if !ok {
			return errors.New("udp requires hysteria udp transport")
		}

		requestDone := func() error {
			defer timer.SetTimeout(sessionPolicy.Timeouts.DownlinkOnly)

			writer := &UDPWriter{
				writer: conn,
				addr:   target.NetAddr(),
			}

			if err := buf.Copy(link.Reader, writer, buf.UpdateActivity(timer)); err != nil {
				return errors.New("failed to transport all UDP request").Base(err)
			}

			return nil
		}

		responseDone := func() error {

View on GitHub (pinned to 7d214f8b09)

When it happens

Trigger: Thrown at proxy/hysteria/client.go:127 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of XTLS/Xray-core@7d214f8b09 (2026-08-15). Data as JSON: /api/errors/f227cedc98eda0fd. Report an issue: GitHub.