XTLS/Xray-core · error

failed to read command

Error message

failed to read command

What it means

Error "failed to read command" thrown in XTLS/Xray-core.

Source

Thrown at proxy/trojan/protocol.go:174

	Flow         string
	headerParsed bool
}

// ParseHeader parses the trojan protocol header
func (c *ConnReader) ParseHeader() error {
	var crlf [2]byte
	var command [1]byte
	var hash [56]byte
	if _, err := io.ReadFull(c.Reader, hash[:]); err != nil {
		return errors.New("failed to read user hash").Base(err)
	}

	if _, err := io.ReadFull(c.Reader, crlf[:]); err != nil {
		return errors.New("failed to read crlf").Base(err)
	}

	if _, err := io.ReadFull(c.Reader, command[:]); err != nil {
		return errors.New("failed to read command").Base(err)
	}

	network := net.Network_TCP
	if command[0] == commandUDP {
		network = net.Network_UDP
	}

	addr, port, err := addrParser.ReadAddressPort(nil, c.Reader)
	if err != nil {
		return errors.New("failed to read address and port").Base(err)
	}
	c.Target = net.Destination{Network: network, Address: addr, Port: port}

	if _, err := io.ReadFull(c.Reader, crlf[:]); err != nil {
		return errors.New("failed to read crlf").Base(err)
	}

	c.headerParsed = true

View on GitHub (pinned to 7d214f8b09)

When it happens

Trigger: Thrown at proxy/trojan/protocol.go:174 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/c5e3fa7e7c62adb0. Report an issue: GitHub.