Java

SSH Tunnel Per-Client Logging and Client Identifier

Demonstrates the ClientLogDir and ClientIdentifier properties. When ClientLogDir is set, a separate log file is created for each tunnel client; ClientIdentifier is the SSH client-identification string sent during the handshake.

Note: The log paths are relative to the application's current working directory. Absolute paths may also be used.

Background: When many clients share one tunnel, a single combined log is hard to follow, so ClientLogDir gives each connection its own file — the fastest way to diagnose one misbehaving client. ClientIdentifier sets the version string the server sees; overriding the default is occasionally needed for compatibility with servers that key behavior off the client identification, or simply to label your application in server logs.

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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 SshTunnel per-client logging properties ClientLogDir and ClientIdentifier.

    CkSshTunnel tunnel = new CkSshTunnel();

    //  When ClientLogDir is set, a separate log file is created for each tunnel client in this
    //  directory, which is useful for troubleshooting individual connections.
    tunnel.put_ClientLogDir("qa_output/client_logs");

    //  The SSH client-identification string sent to the SSH server during the handshake.
    tunnel.put_ClientIdentifier("SSH-2.0-MyTunnelApp_1.0");

    tunnel.put_DestHostname("db.internal.example.com");
    tunnel.put_DestPort(5432);

    int sshPort = 22;
    success = tunnel.Connect("ssh.example.com",sshPort);
    if (success == false) {
        System.out.println(tunnel.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 = tunnel.AuthenticatePw("mySshLogin",password);
    if (success == false) {
        System.out.println(tunnel.lastErrorText());
        return;
        }

    int listenPort = 1080;
    success = tunnel.BeginAccepting(listenPort);
    if (success == false) {
        System.out.println(tunnel.lastErrorText());
        return;
        }

    System.out.println("Tunnel running; each client is logged in " + tunnel.clientLogDir());

    boolean waitForThreadExit = true;
    success = tunnel.CloseTunnel(waitForThreadExit);
    if (success == false) {
        System.out.println(tunnel.lastErrorText());
        return;
        }
  }
}