How to disable echo when sending a terminal command using apache-commons-net TelnetClient

Question

So, I have this class that uses the org.apache.commons.net.telnet.TelnetClient class. It attempts to send commands and read the response.

public class Automa         


        

Answer 1

Interesting problem. To summarize my effort: I didn't get it working properly But here are some of my findings:

You cannot write IAC DON'T ECHO directly to the data channel, this is done with commands and options like this example

int[] msg = {TelnetCommand.DONT,TelnetOption.ECHO};
telnet.sendSubnegotiation(msg);

You can register telnet.registerNotifHandler(new MyNotificationHandler()); to debug the commands during connection setup

public class MyNotificationHandler implements TelnetNotificationHandler
{
  @Override
  public void receivedNegotiation(int negotiation_code, int option_code)
  {
    System.out.println("--->"+get(negotiation_code)+" "
                             +TelnetOption.getOption(option_code));
  }

  private String get(int i)
  {
    if(i==TelnetNotificationHandler.RECEIVED_DO){return "RECEIVED_DO";}
    else if(i==TelnetNotificationHandler.RECEIVED_DONT){return "RECEIVED_DONT";}
    else if(i==TelnetNotificationHandler.RECEIVED_WILL){return "RECEIVED_WILL";}
    else if(i==TelnetNotificationHandler.RECEIVED_WONT){return "RECEIVED_WONT";}
    else if(i==TelnetNotificationHandler.RECEIVED_COMMAND)
                                                    {return "RECEIVED_COMMAND";}
    return "UNKNOWN";
    }
}