private String getIpAddress(byte[] bs, int offset) {
        // storage server ID
        if (bs[0] == 0 || bs[3] == 0) {
            return "";
        }

        int n;
        StringBuilder sbResult = new StringBuilder(16);
        for (int i = offset; i < offset + 4; i++) {
            n = (bs[i] >= 0) ? bs[i] : 256 + bs[i];
            if (sbResult.length() > 0) {
                sbResult.append(".");
            }
            sbResult.append(String.valueOf(n));
        }
        return sbResult.toString();
    }