lookup.java

        try {
            String[] split = ip.split("\\.");
            StringBuilder lookup = new StringBuilder();
            for (int i = split.length - 1; i >= 0; i--) {
                lookup.append(split[i]);
                lookup.append(".");
            }
            lookup.append("xbl.spamhaus.org.");
            if (java.net.InetAddress.getByName(lookup.toString()) != null) {
                return "Your IP address is flagged as unsafe by spamhaus.org/xbl";
            }
        } catch (Exception ex) {
        }