Overview

The Telnet server can be disabled on any Omega Series, Ultra Series, or MaxColor Series device. Once disabled, the device will no longer accept Telnet connections on TCP port 23.

This setting applies to an individual device. Repeat the procedure on each device where Telnet access must be disabled.

Before You Begin

Before disabling Telnet:

• Confirm that you have network access to the device.
• Confirm that the device webUI and webUI CLI are available.
• Verify that the control system does not depend on a Telnet connection to TCP port 23.

For device access instructions, see How to Access a Device (Omega, Ultra, and MaxColor Series).

Disable Telnet

1. Access the device CLI through Telnet or the webUI.

2. Execute the following commands:

   astparam s telnetd_param --help
   astparam save
   reboot

3. Wait for the device to reboot.

When the device restarts, the Telnet process will not start and connections to TCP port 23 will be refused.

Available Services

Disabling Telnet does not disable the following device services:

• webUI access, including the webUI CLI
• HTTP API access
• Source switching through the HTTP API using POST /command/switch

HTTP API Switching Example

Send the following request to a Just Add Power device:

POST /command/switch

Include the Decoder Matrix ID in the rx array and the Encoder Matrix ID as the tx value:

{
  "rx": [
    0
  ],
  "tx": 0
}

Restore Telnet

1. Open the device webUI and access its CLI.

2. Execute the following commands to remove the telnetd_param setting:

   astparam s telnetd_param
   astparam save
   reboot

3. Wait for the device to reboot.

The Telnet server will start normally after the reboot, restoring access through TCP port 23.