orgLevelFlow_blacklistedServers_check: function(orgLevelPolicy, flow) {


        var Addr = require('netaddr').Addr;
        var rangeCheck = require('range_check');

        // General rules to check for blacklisted server activity:
        // 1: if client is in org's IP subnets && server is in org's blacklisted IP
        //    ==> raise alert as this means that an org's entiry is trying to talk to a blacklisted entitiy
        // 2: if server is in org's IP subnets && client is in org's blacklisted IP
        //    ==> raise alert as this means that an outside blacklisted entitiy is trying to talk to an org's entitiy
        //
        //get orgLevelPolicy's IP subnets & convert it to array
        var orgLevelIpSubnets = orgLevelPolicy.ipSubnets.split(",");
        //get orgLevelPolicy's blacklistedServers & convert it to array
        var orgLevelBlacklistedServers = orgLevelPolicy.blacklistedServers.split(",");

        // only check for ipv4 addresses for now.
        // @TODO: Implement ipv6 range check also. Note: netAddr does not support ipv6 range owing to JS int 64bit / 128bit not existing
        if (rangeCheck.isV4(flow.netflow.client_addr) && rangeCheck.isV4(flow.netflow.server_addr)) {

            for (var i = 0; i < orgLevelIpSubnets.length; i++) {

                // if client_addr is part of ipSubnet:
                if (Addr(orgLevelIpSubnets[i]).contains(Addr(flow.netflow.client_addr))) {

                    for (var j = 0; j < orgLevelBlacklistedServers.length; j++) {
                        if (Addr(orgLevelBlacklistedServers[j]).contains(Addr(flow.netflow.server_addr))) {
                            // console.log("client: " + flow.netflow.client_addr + " Server: " + flow.netflow.server_addr);
                            // if there exists an open alert, then append to that alert.

                            if (alerts.findOne({
                                    alertLevel: "orgLevelAlert",
                                    alertCategory: "blacklistedServersViolationAlert",
                                    alertState: "open"
                                })) {
                                // append
                                // console.log("Appending to existing open alert");
                                alerts.update({
                                    alertLevel: "orgLevelAlert",
                                    alertCategory: "blacklistedServersViolationAlert",
                                    alertState: "open"
                                }, {
                                    $set: {
                                        "misc.updatedTime": new Date()
                                    },
                                    $inc: {
                                        flowCount: 1
                                    },
                                    $addToSet: {
                                        blacklistedCommunication: {
                                            client: flow.netflow.client_addr,
                                            server: flow.netflow.server_addr
                                        }
                                    }
                                });
                            }
                            // if there is a closed alert, then open a new alert.
                            // if there is no alert, create a new one. (No need to check this condition)
                            else {
                                console.log("Creating new alert");
                                alerts.insert({
                                    alertLevel: "orgLevelAlert",
                                    alertCategory: "blacklistedServersViolationAlert",
                                    alertState: "open",
                                    flowCount: 1,
                                    blacklistedCommunication: [{
                                        client: flow.netflow.client_addr,
                                        server: flow.netflow.server_addr,
                                    }],
                                    misc: {
                                        createdBy: "system",
                                        updatedBy: "system",
                                        createdTime: new Date(),
                                        updatedTime: new Date()
                                    }
                                });
                            }
                        }

                    }

                } // client server pair 1


                //if server_addr is part of the ipSubnet:
                else if (Addr(orgLevelIpSubnets[i]).contains(Addr(flow.netflow.server_addr))) {
                    for (var j = 0; j < orgLevelBlacklistedServers.length; j++) {
                        if (Addr(orgLevelBlacklistedServers[j]).contains(Addr(flow.netflow.client_addr))) {
                            // console.log("client: " + flow.netflow.client_addr + " Server: " + flow.netflow.server_addr);
                            // if there exists an open alert, then append to that alert.

                            if (alerts.findOne({
                                    alertLevel: "orgLevelAlert",
                                    alertCategory: "blacklistedServersViolationAlert",
                                    alertState: "open"
                                })) {
                                // append
                                // console.log("Appending to existing open alert");
                                alerts.update({
                                    alertLevel: "orgLevelAlert",
                                    alertCategory: "blacklistedServersViolationAlert",
                                    alertState: "open"
                                }, {
                                    $set: {
                                        "misc.updatedTime": new Date()
                                    },
                                    $inc: {
                                        flowCount: 1
                                    },
                                    $addToSet: {
                                        blacklistedCommunication: {
                                            client: flow.netflow.client_addr,
                                            server: flow.netflow.server_addr
                                        }
                                    }
                                });
                            }
                            // if there is a closed alert, then open a new alert.
                            // if there is no alert, create a new one. (No need to check this condition)
                            else {
                                console.log("Creating new alert");
                                alerts.insert({
                                    alertLevel: "orgLevelAlert",
                                    alertCategory: "blacklistedServersViolationAlert",
                                    alertState: "open",
                                    flowCount: 1,
                                    blacklistedCommunication: [{
                                        client: flow.netflow.client_addr,
                                        server: flow.netflow.server_addr
                                    }],
                                    misc: {
                                        createdBy: "system",
                                        updatedBy: "system",
                                        createdTime: new Date(),
                                        updatedTime: new Date()
                                    }
                                });
                            }
                        }
                    }
                } //client server pair 2
            }
        } //end of if it's an ipv4
    }