* potential NTLM fallback (if the server does not support kerberos).
     * 
     * @param subject
     *            represents the user who perform Kerberos authentication. Should at least contain a TGT for the user.
     * @param domain
     *            domain for NTLM fallback
     * @param username
     *            user for NTLM fallback
     * @param password

     * {@inheritDoc}
     *
     * @see javax.security.auth.callback.CallbackHandler#handle(javax.security.auth.callback.Callback[])
     */
    @Override
    public void handle ( Callback[] callbacks ) throws IOException, UnsupportedCallbackException {
        for ( Callback cb : callbacks ) {
            if ( log.isDebugEnabled() ) {
                log.debug("Got callback " + cb.getClass().getName());
            }

        try ( SmbSessionImpl treesess = t.getSession() ) {
            if ( treesess.getCredentials().isAnonymous() || treesess.getCredentials().isGuest() ) {
                // refresh anonymous session or fallback to anonymous from guest login
                try ( SmbSessionInternal s = trans
                        .getSmbSession(this.ctx.withAnonymousCredentials(), treesess.getTargetHost(), treesess.getTargetDomain())

         * Login with no credentials
         */
        NULL,
        /**
         * Guest authentication
         * 
         * Allows login with invalid credentials (username and/or password)
         * Fallback to anonymous authentication is permitted
         */
        GUEST,
        /**
         * Regular user authentication
         */
        USER
    }

     */
    int getLanManCompatibility ();


    /**
     * 
     * Property <tt>jcifs.smb.allowNTLMFallback</tt> (boolean, default true)
     * 
     * @return whether to allow fallback from kerberos to NTLM
     */
    boolean isAllowNTLMFallback ();


    /**
     * Property <tt>jcifs.smb.useRawNTLM</tt> (boolean, default false)
     *