Credentials cred = getCredentials();
        if ( cred instanceof SmbRenewableCredentials ) {
            SmbRenewableCredentials renewable = (SmbRenewableCredentials) cred;
            CredentialsInternal renewed = renewable.renew();
            if ( renewed != null ) {
                this.creds = renewed;
                return true;
            }
        }
        NtlmAuthenticator auth = NtlmAuthenticator.getDefault();