Java

Send an SSH IGNORE Message

Demonstrates the Chilkat Ssh.SendIgnore method, which sends an SSH IGNORE message. It takes no arguments. The server does not reply, but a successful send helps confirm the connection is still writable. No channel is required.

Background: The SSH IGNORE message is discarded by the peer by design; its usefulness is as a lightweight keep-alive or liveness probe. Because it exercises the actual write path, a successful SendIgnore is stronger evidence than CheckConnection that the link is still usable, without side effects on any channel.

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Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean success = false;

    //  Demonstrates the Ssh.SendIgnore method, which sends an SSH IGNORE message.  It takes no
    //  arguments.  The server does not reply, but a successful send helps confirm the connection is
    //  still writable.  No channel is required.

    CkSsh ssh = new CkSsh();

    //  Connect to the SSH server.  Port 22 is the usual SSH port.
    int sshPort = 22;
    success = ssh.Connect("ssh.example.com",sshPort);
    if (success == false) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    //  Normally you would not hard-code the password in source.  You should instead obtain it
    //  from an interactive prompt, environment variable, or a secrets vault.
    String password = "mySshPassword";

    success = ssh.AuthenticatePw("mySshLogin",password);
    if (success == false) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    //  Send an IGNORE message to verify the connection is still writable.
    success = ssh.SendIgnore();
    if (success == false) {
        System.out.println(ssh.lastErrorText());
        return;
        }

    System.out.println("IGNORE message sent.");

    ssh.Disconnect();
  }
}