How can I display the Authentication Banner

Some SSH servers are configured to show an authentication banner to the user prior to authentication.

If you want to display this in your own application you can configure a BannerDisplay callback on the client's context.

First, implement BannerDisplay interface, in this simple example we will just write the message to System.out.

BannerDisplay display = new BannerDisplay() { 
   @Override 
   public void displayBanner(String message) { 
      System.out.println(message); 
   } 
};

Next, we just have to configure this on the SshClientContext for each connection. The simplest way of doing this is to create and pass a SshClientContext instance to your SshClient

try(SshClient ssh = new SshClient("localhost", 
    22,
   "lee",  
   new SshClientContext().setBannerDisplay(display), 
   "xxxxxx".toCharArray())) { 

}

Alternatively, you could extend SshClient with your own class and configure the BannerDisplay instance by overriding the SshClient's protected configure method.

protected void configure(SshClientContext sshContext) { 
   sshContext.setBannerDisplay(new BannerDisplay() { 
      @Override 
      public void displayBanner(String message) { 
         System.out.println(message); 
      } 
   });
}