if (this.sessionKey == null) {
            throw new CIFSException("No session key available");
        }
        return this.sessionKey;
    }

    @Override
    public SmbTreeImpl getSmbTree(String share, String service) {
        if (share == null) {
            share = "IPC$";
        }

        synchronized (this.trees) {
            for (SmbTreeImpl t : this.trees) {

                SmbSessionInternal smbSession = smbTransport.getSmbSession(tf, dc.getHostName(), null).unwrap(SmbSessionInternal.class);
                SmbTreeInternal tree = smbSession.getSmbTree(tf.getConfig().getLogonShare(), null).unwrap(SmbTreeInternal.class)) {
            tree.connectLogon(tf);
        }
    }

    /**
     * Perform health check on connections
     */

                ssn = trans.getSmbSession(NtlmPasswordAuthentication.NULL);
                tree = ssn.getSmbTree(null, null);
            } else if ((a = NtlmAuthenticator.requestNtlmPasswordAuthentication(url.toString(), sae)) != null) {
                auth = a;
                ssn = trans.getSmbSession(auth);
                tree = ssn.getSmbTree(share, null);
                tree.inDomainDfs = dfs.resolve(hostName, tree.share, null, auth) != null;

        }

        try (SmbSessionImpl sess = getSmbSession(ctx, targetHost, targetDomain);
                SmbTransportImpl transport = sess.getTransport();
                SmbTreeImpl ipc = sess.getSmbTree("IPC$", null)) {

            final DfsReferralRequestBuffer dfsReq = new DfsReferralRequestBuffer(path, 3);
            DfsReferralResponseBuffer dfsResp;
            if (isSMB2()) {