🧾 Description
Matrix scanners use port 23 (Telnet) as an internal debug communication channel. While the Telnet service is present and visible on the device, it is not used to transmit sensitive information.
The Telnet server is a built-in component of the scanner firmware and cannot be disabled through device configuration or settings.
🛠️ Resolution Steps
Although the Telnet server cannot be disabled, it is possible to prevent information from being accessible through port 23 by occupying the port locally on the device.
Steps
Open two TCP client connections to localhost (127.0.0.1) on port 23.
Keep both TCP client sessions active.
Once both connections are established, port 23 will remain open, but the Telnet server information will no longer be available through that port.
Expected Result
Port 23 continues to appear as open.
No sensitive data is transmitted through the Telnet debug channel.
Telnet server information is effectively hidden from external access attempts.
The Telnet service itself remains enabled, as disabling it is not supported.
Additional Notes
This behavior is by design and is intended for debugging purposes.
There is currently no supported method to disable the Telnet server on Matrix scanners.
The workaround described above only hides Telnet server information; it does not close or disable port 23.