synchronized ( this.dcLock ) {
            CacheEntry<DfsReferralDataInternal> ce = this.dcCache.get(dom);
            if ( ce != null && System.currentTimeMillis() > ce.expiration ) {
                ce = null;
            }
            if ( ce != null ) {
                DfsReferralDataInternal ri = ce.map.get(DC_ENTRY);
                if ( ri == NEGATIVE_ENTRY ) {
                    return null;

        }
        catch ( IOException ce ) {
            if ( getContext().getConfig().isPort139FailoverEnabled() ) {
                this.port = ( this.port == 0 || this.port == DEFAULT_PORT ) ? 139 : DEFAULT_PORT;
                this.smb2 = false;
                this.mid.set(0);
                resp = negotiate(this.port);
            }
            else {
                throw ce;
            }
        }

         */

        SmbComNegotiateResponse resp = new SmbComNegotiateResponse( server );
        try {
            negotiate( port, resp );
        } catch( ConnectException ce ) {
            // Try an alternate port if there was an issue communicating to the server
            // Only set the alternate port to the port property if it was successful