Patent Publication Number: US-2021168142-A1

Title: Disaster recovery for a cloud-based security service

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     The present patent application/patent is a continuation-in-part of U.S. patent application Ser. No. 16/922,353, filed Jul. 7, 2020, and entitled “Enforcing security policies on mobile devices in a hybrid architecture,” which is a continuation-in-part of U.S. patent application Ser. No. 15/900,951, filed Feb. 21, 2018, and entitled “SYSTEMS AND METHODS FOR CLOUD BASED UNIFIED SERVICE DISCOVERY AND SECURE AVAILABILITY,” which is a continuation of U.S. patent application Ser. No. 15/153,108, filed May 12, 2016 (now U.S. Pat. No. 9,935,955, issued Apr. 3, 2018) and entitled “SYSTEMS AND METHODS FOR CLOUD BASED UNIFIED SERVICE DISCOVERY AND SECURE AVAILABILITY,” which claims the benefit of priority of Indian Patent Application No. 201611010521, filed on Mar. 28, 2016, and entitled “SYSTEMS AND METHODS FOR CLOUD BASED UNIFIED SERVICE DISCOVERY AND SECURE AVAILABILITY,” the contents of each are incorporated by reference herein in their entirety. 
    
    
     FIELD OF THE DISCLOSURE 
     The present disclosure generally relates to computer networking systems and methods. More particularly, the present disclosure relates to systems and methods for disaster recovery for a cloud-based security service. 
     BACKGROUND OF THE DISCLOSURE 
     Corporate applications (also referred to as enterprise applications, private applications, cloud applications, etc.) are going mobile, as are the vast majority of users (i.e., employees, partners, contractors, etc. of an enterprise). The traditional view of an enterprise network (i.e., corporate, private, etc.) included a well-defined perimeter defended by various appliances (e.g., firewalls, intrusion prevention, advanced threat detection, etc.). In this traditional view, mobile users utilize a Virtual Private Network (VPN), etc. and have their traffic backhauled into the well-defined perimeter. This worked when mobile users represented a small fraction of the users, i.e., most users were within the well-defined perimeter. However, this is no longer the case—the definition of the workplace is no longer confined to within the well-defined perimeter. This results in an increased risk for the enterprise data residing on unsecured and unmanaged devices as well as the security risks in access to the Internet. 
     Further, having all traffic through the well-defined perimeter simply does not scale. On the user device side, several client-side agents provide security and compliance, but there are inherent challenges with these agents like battery drainage issues, limited signature based-detection ability, high processor consumption, etc. As such, security on mobile devices is not as practical as on desktop, laptops, etc. Accordingly, cloud-based security solutions have emerged, such as Zscaler Internet Access (ZIA) and Zscaler Private Access (ZPA), available from Zscaler, Inc., the applicant, and assignee of the present application. With mobile devices and a cloud-based security system, there is an opportunity to leverage the benefits of client-side protection with cloud-based protection with the goals of reducing bandwidth, reducing latency, having an access solution when there are reachability or connectivity issues, etc. 
     Also, such cloud-based security services provide significant advantages in scalability, simplicity, efficiency, etc. With this approach, security processing is in the cloud, off the device. Of course, cloud-based security services are designed for high availability, redundancy, geographic distribution, etc. However, there can always be situations where a device has network access but there is not connectivity to the cloud. That is, there can be a “disaster” where the cloud is unavailable to provide security processing for any reason, e.g., network congestion, server overload, failures in the cloud, etc. In such situations, user access would not have the security processing. 
     BRIEF SUMMARY OF THE DISCLOSURE 
     The present disclosure relates to systems and methods for disaster recovery for a cloud-based security service. In particular, the disaster recovery can include a hybrid architecture. In particular, the hybrid architecture is one where there is some client-side processing of security functions and some cloud-based processing, in conjunction with one another. The objective is to leverage the benefits of both approaches while reducing or eliminating the shortcomings. The present disclosure includes a lightweight agent or application (“client connector”) that is executed on mobile devices with the agent supporting application firewall, Uniform Resource Locator (URL) filtering, Data Loss Prevention (DLP), etc. Further, the lightweight agent or application is synchronized with a cloud-based security system for updates, processing in the cloud, etc. This approach with a hybrid architecture enforces security policies on a mobile device while leveraging the cloud in an efficient and optimized manner. For disaster recovery, the lightweight agent or application can be used to cache user activity for local policy, such as based on user browsing, and use the cached local policy in a failure scenario. Thus, there can be security processing without the cloud-based system and without failing open (with no security processing). 
     In various embodiments, the present disclosure includes a method implementing steps, a user device configured to implement the steps, and the steps as computer-executable instructions stored in a non-transitory computer-readable medium. The steps include disaster recovery for a cloud-based security service. The steps include intercepting traffic on the user device; forwarding the traffic to a cloud-based system for security processing therein; and, responsive to unavailability of the cloud-based system preventing the forwarding, performing local security processing of the traffic at the user device including determining whether the traffic is allowed based on a cache at the user device, forwarding the traffic separate from the cloud-based system when it is allowed, and blocking the traffic when it is not allowed. 
     The steps can further include updating the cache based on the forwarding and actions taken by the cloud-based system. The steps can further include obtaining a list for the cache that contains pre-configured domains. The list can be based on a tenant associated with the user device. The traffic can be blocked based on a domain being included or excluded in the cache. The steps can further include maintaining access logs locally at the user device for the local security processing; and forwarding the access logs to the cloud-based system after it is available. The unavailability can be based on the cloud-based system being down beyond a threshold. The local security processing can be configured by a tenant. The local security processing can include Zero Trust Network Access to an application included in an enterprise network, and wherein the steps can include providing a secure connection to the application included in the enterprise network based on the cache. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure is illustrated and described herein with reference to the various drawings, in which like reference numbers are used to denote like system components/method steps, as appropriate, and in which: 
         FIG. 1  is a network diagram of a cloud-based system offering security as a service; 
         FIG. 2  is a network diagram of an example implementation of the cloud-based system; 
         FIG. 3  is a block diagram of a server that may be used in the cloud-based system of  FIGS. 1 and 2  or the like; 
         FIG. 4  is a block diagram of a user device that may be used with the cloud-based system of  FIGS. 1 and 2  or the like; 
         FIG. 5  is a network diagram of the cloud-based system illustrating an application on user devices with users configured to operate through the cloud-based system; 
         FIG. 6  is a network diagram of a Zero Trust Network Access (ZTNA) application utilizing the cloud-based system of  FIGS. 1 and 2 ; 
         FIG. 7  is a network diagram of the cloud-based system of  FIGS. 1 and 2  in an application of digital experience monitoring; 
         FIG. 8  is a network diagram of a unified agent application and associated connectivity and functionality with the cloud-based system; 
         FIG. 9  is a network diagram of example workflow of the unified agent application; 
         FIG. 10  is a flow diagram of an event sequence associated with the unified agent application; 
         FIG. 11  is a logical diagram of functional components of the unified agent application; 
         FIG. 12  is a flowchart of a proxy authentication process to the cloud-based system; 
         FIG. 13  is a flowchart of a VPN authentication process to the cloud-based system; 
         FIG. 14  is a flowchart of a device enrollment process for the client user device and the unified agent application; 
         FIG. 15  is a flowchart of a traffic interception process implemented through the unified agent application; 
         FIG. 16  is a flow diagram of traffic interception and splitting using the unified agent application; 
         FIG. 17  is a flow diagram of tunnel forwarding rules by the unified agent application; 
         FIG. 18  is a flowchart of a service drive split tunneling process; 
         FIG. 19  is a flowchart of a process for security processing in a hybrid architecture; and 
         FIG. 20  is a flowchart of a process for disaster recovery via the hybrid architecture of  FIG. 19 . 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     Again, the present disclosure relates to systems and methods for disaster recovery for a cloud-based security service. In particular, the disaster recovery can include a hybrid architecture. In particular, the hybrid architecture is one where there is some client-side processing of security functions and some cloud-based processing, in conjunction with one another. The objective is to leverage the benefits of both approaches while reducing or eliminating the shortcomings. The present disclosure includes a lightweight agent or application (“client connector”) that is executed on mobile devices with the agent supporting application firewall, Uniform Resource Locator (URL) filtering, Data Loss Prevention (DLP), etc. Further, the lightweight agent or application is synchronized with a cloud-based security system for updates, processing in the cloud, etc. This approach with a hybrid architecture enforces security policies on a mobile device while leveraging the cloud in an efficient and optimized manner. For disaster recovery, the lightweight agent or application can be used to cache user activity for local policy, such as based on user browsing, and use the cached local policy in a failure scenario. Thus, there can be security processing without the cloud-based system and without failing open (with no security processing). 
     Additionally, the present disclosure relates to systems and methods for service driven split tunneling of mobile network traffic. The systems and methods include an app or agent on a user device (e.g., a mobile device) which performs split tunneling based upon port, protocol, and destination IP address instead of just destination IP. This provides granular controls to IT administrators to steer a user&#39;s network traffic based upon the demands of the service. This is very advantageous from a scalability point of view as the demands for a particular service grow, that traffic can be individually distributed, load-balanced, and served without impacting traffic of other services. This form of split tunneling also allows for efficient usage of resources both on the end user&#39;s device as well as backend concentrators. For instance, if all traffic, including HTTP and HTTPS, is tunneled via an SSL VPN, there is an overhead of decrypting SSL traffic twice, one for the transport and the other for the application itself. While splitting traffic based upon the protocol, the HTTPS transport can go unencrypted since the HTTPS traffic itself is encrypted. This saves both the client and the avoiding encryption and decryption twice, saving a significant amount of computational power on all ends. 
     Another benefit of this form of split tunneling is that it takes into account the quality of service requirements for different protocols. For example, in a conventional VPN, all VOIP and UDP traffic will be tunneled over an SSL VPN with all other TCP traffic as well. Since all these protocols have different service requirements, the traditional VPN generally underperforms and is difficult to scale. With this service driven split tunneling, VOIP over UDP traffic can be tunneled separately to a specific UDP traffic concentrator that is designed for handling large volumes of such traffic. In this case, VOIP traffic does not need to fight with other protocols through its intended destination. In another use case, an admin may altogether decide not to tunnel VOIP traffic and go directly from the user&#39;s device. Note that this kind of granularity is not possible with split tunneling based upon destination IP address alone. The service driven split tunneling further allows for on-demand embarking (or disembarking) of particular network traffic, i.e., whenever the IT infrastructure is ready to support a new protocol, the agent can start (or stop) tunneling that traffic based upon the configured rules. 
     Further, the present disclosure relates to systems and methods for cloud-based unified service discovery and secure availability. The systems and methods enable a user to connect to multiple cloud services through the dynamic discovery of available services, followed by authentication and access as exposed in the corresponding service protocol. The systems and methods address the unmanageable growth of mobility and cloud-based services, which have led to a proliferation of individual applications for access to individual services. The systems and method can be implemented through a mobile application (“app”) which overcomes the hassle of deploying and managing several applications across a gamut of mobile devices, operating systems, and mobile networks to gain secure access to the cloud-based Internet or intranet resources. The mobile application can uniquely perform a Dynamic evaluation of Network and Service Discovery, Unified Enrollment to all services, application-dependent service enablement, Service protocol learning, Service Availability through secure network traffic forwarding tunnels, and the like. 
     Again, enterprises have a strong need to provide secure access to cloud services to its end users. The growth of mobility and cloud in the IT enterprise has made it impossible for IT admins to deploy individual applications for individual services. The mobile app associated with the systems and methods overcomes these limitations through the dynamic discovery of available services to the end user, followed by authentication and access to individual services. Further, the mobile app insightfully learns the protocol for each service and establishes a secure tunnel to the service. In essence, the mobile app is one app that an enterprise may use to provide secure connectivity to the Internet and diversified internal corporate applications. At the time of user enrollment, the mobile app will discover all services provided by the enterprise cloud and will enroll the user in all of those services. It will then set up secure tunnels for each service depending upon the port, protocol, and intended destination of requested traffic. 
     The mobile app will also discover all applications provided within the enterprise cloud along with a Global VPN (GVPN) service and show the available services to end users. Endpoint Applications today provide one service for a specific network function (such as a VPN to a corporate network, web security, antivirus to access the Internet). The mobile app can be used to enable all these services with single enrollment. The mobile app will provide services to darknet applications along with securing the Internet traffic. The mobile app can set up a local network on the mobile device. 
     Example Cloud-Based System Architecture 
       FIG. 1  is a network diagram of a cloud-based system  100  offering security as a service. Specifically, the cloud-based system  100  can offer a Secure Internet and Web Gateway as a service to various users  102 , as well as other cloud services. In this manner, the cloud-based system  100  is located between the users  102  and the Internet as well as any cloud services  106  (or applications) accessed by the users  102 . As such, the cloud-based system  100  provides inline monitoring inspecting traffic between the users  102 , the Internet  104 , and the cloud services  106 , including Secure Sockets Layer (SSL) traffic. The cloud-based system  100  can offer access control, threat prevention, data protection, etc. The access control can include a cloud-based firewall, cloud-based intrusion detection, Uniform Resource Locator (URL) filtering, bandwidth control, Domain Name System (DNS) filtering, etc. The threat prevention can include cloud-based intrusion prevention, protection against advanced threats (malware, spam, Cross-Site Scripting (XSS), phishing, etc.), cloud-based sandbox, antivirus, DNS security, etc. The data protection can include Data Loss Prevention (DLP), cloud application security such as via Cloud Access Security Broker (CASB), file type control, etc. 
     The cloud-based firewall can provide Deep Packet Inspection (DPI) and access controls across various ports and protocols as well as being application and user aware. The URL filtering can block, allow, or limit website access based on policy for a user, group of users, or entire organization, including specific destinations or categories of URLs (e.g., gambling, social media, etc.). The bandwidth control can enforce bandwidth policies and prioritize critical applications such as relative to recreational traffic. DNS filtering can control and block DNS requests against known and malicious destinations. 
     The cloud-based intrusion prevention and advanced threat protection can deliver full threat protection against malicious content such as browser exploits, scripts, identified botnets and malware callbacks, etc. The cloud-based sandbox can block zero-day exploits (just identified) by analyzing unknown files for malicious behavior. Advantageously, the cloud-based system  100  is multi-tenant and can service a large volume of the users  102 . As such, newly discovered threats can be promulgated throughout the cloud-based system  100  for all tenants practically instantaneously. The antivirus protection can include antivirus, antispyware, antimalware, etc. protection for the users  102 , using signatures sourced and constantly updated. The DNS security can identify and route command-and-control connections to threat detection engines for full content inspection. 
     The DLP can use standard and/or custom dictionaries to continuously monitor the users  102 , including compressed and/or SSL-encrypted traffic. Again, being in a cloud implementation, the cloud-based system  100  can scale this monitoring with near-zero latency on the users  102 . The cloud application security can include CASB functionality to discover and control user access to known and unknown cloud services  106 . The file type controls enable true file type control by the user, location, destination, etc. to determine which files are allowed or not. 
     For illustration purposes, the users  102  of the cloud-based system  100  can include a mobile device  110 , a headquarters (HQ)  112  which can include or connect to a data center (DC)  114 , Internet of Things (IoT) devices  116 , a branch office/remote location  118 , etc., and each includes one or more user devices (an example user device  300  is illustrated in  FIG. 3 ). The devices  110 ,  116 , and the locations  112 ,  114 ,  118  are shown for illustrative purposes, and those skilled in the art will recognize there are various access scenarios and other users  102  for the cloud-based system  100 , all of which are contemplated herein. The users  102  can be associated with a tenant, which may include an enterprise, a corporation, an organization, etc. That is, a tenant is a group of users who share a common access with specific privileges to the cloud-based system  100 , a cloud service, etc. In an embodiment, the headquarters  112  can include an enterprise&#39;s network with resources in the data center  114 . The mobile device  110  can be a so-called road warrior, i.e., users that are off-site, on-the-road, etc. 
     Further, the cloud-based system  100  can be multi-tenant, with each tenant having its own users  102  and configuration, policy, rules, etc. One advantage of the multi-tenancy and a large volume of users is the zero-day/zero-hour protection in that a new vulnerability can be detected and then instantly remediated across the entire cloud-based system  100 . The same applies to policy, rule, configuration, etc. changes—they are instantly remediated across the entire cloud-based system  100 . As well, new features in the cloud-based system  100  can also be rolled up simultaneously across the user base, as opposed to selective and time-consuming upgrades on every device at the locations  112 ,  114 ,  118 , and the devices  110 ,  116 . 
     Logically, the cloud-based system  100  can be viewed as an overlay network between users (at the locations  112 ,  114 ,  118 , and the devices  110 ,  116 ) and the Internet  104  and the cloud services  106 . Previously, the IT deployment model included enterprise resources and applications stored within the data center  114  (i.e., physical devices) behind a firewall (perimeter), accessible by employees, partners, contractors, etc. on-site or remote via Virtual Private Networks (VPNs), etc. The cloud-based system  100  is replacing the conventional deployment model. The cloud-based system  100  can be used to implement these services in the cloud without requiring the physical devices and management thereof by enterprise IT administrators. As an ever-present overlay network, the cloud-based system  100  can provide the same functions as the physical devices and/or appliances regardless of geography or location of the users  102 , as well as independent of platform, operating system, network access technique, network access provider, etc. 
     There are various techniques to forward traffic between the users  102  at the locations  112 ,  114 ,  118 , and via the devices  110 ,  116 , and the cloud-based system  100 . Typically, the locations  112 ,  114 ,  118  can use tunneling where all traffic is forward through the cloud-based system  100 . For example, various tunneling protocols are contemplated, such as Generic Routing Encapsulation (GRE), Layer Two Tunneling Protocol (L2TP), Internet Protocol (IP) Security (IPsec), customized tunneling protocols, etc. The devices  110 ,  116 , when not at one of the locations  112 ,  114 ,  118  can use a local application that forwards traffic, a proxy such as via a Proxy Auto-Config (PAC) file, and the like. A key aspect of the cloud-based system  100  is all traffic between the users  102  and the Internet  104  or the cloud services  106  is via the cloud-based system  100 . As such, the cloud-based system  100  has visibility to enable various functions, all of which are performed off the user device in the cloud. 
     The cloud-based system  100  can also include a management system  120  for tenant access to provide global policy and configuration as well as real-time analytics. This enables IT administrators to have a unified view of user activity, threat intelligence, application usage, etc. For example, IT administrators can drill-down to a per-user level to understand events and correlate threats, to identify compromised devices, to have application visibility, and the like. The cloud-based system  100  can further include connectivity to an Identity Provider (IDP)  122  for authentication of the users  102  and to a Security Information and Event Management (SIEM) system  124  for event logging. The system  124  can provide alert and activity logs on a per-user  102  basis. 
       FIG. 2  is a network diagram of an example implementation of the cloud-based system  100 . In an embodiment, the cloud-based system  100  includes a plurality of enforcement nodes (EN) 150, labeled as enforcement nodes  150 - 1 ,  150 - 2 ,  150 -N, interconnected to one another and interconnected to a central authority (CA 152 ). The nodes  150 ,  152 , while described as nodes, can include one or more servers, including physical servers, virtual machines (VM) executed on physical hardware, etc. An example of a server is illustrated in  FIG. 2 . The cloud-based system  100  further includes a log router  154  that connects to a storage cluster  156  for supporting log maintenance from the enforcement nodes  150 . The central authority  152  provide centralized policy, real-time threat updates, etc. and coordinates the distribution of this data between the enforcement nodes  150 . The enforcement nodes  150  provide an onramp to the users  102  and are configured to execute policy, based on the central authority  152 , for each user  102 . The enforcement nodes  150  can be geographically distributed, and the policy for each user  102  follows that user  102  as he or she connects to the nearest (or other criteria) enforcement node  150 . Of note, the cloud-based system is an external system meaning it is separate from tenant&#39;s private networks (enterprise networks) as well as from networks associated with the devices  110 ,  116 , and locations  112 ,  118 . 
     The enforcement nodes  150  are full-featured secure internet gateways that provide integrated internet security. They inspect all web traffic bi-directionally for malware and enforce security, compliance, and firewall policies, as described herein. In an embodiment, each enforcement node  150  has two main modules for inspecting traffic and applying policies: a web module and a firewall module. The enforcement nodes  150  are deployed around the world and can handle hundreds of thousands of concurrent users with millions of concurrent sessions. Because of this, regardless of where the users  102  are, they can access the Internet  104  from any device, and the enforcement nodes  150  protect the traffic and apply corporate policies. The enforcement nodes  150  can implement various inspection engines therein, and optionally, send sandboxing to another system. The enforcement nodes  150  include significant fault tolerance capabilities, such as deployment in active-active mode to ensure availability and redundancy as well as continuous monitoring. 
     In an embodiment, customer traffic is not passed to any other component within the cloud-based system  100 , and the enforcement nodes  150  can be configured never to store any data to disk. Packet data is held in memory for inspection and then, based on policy, is either forwarded or dropped. Log data generated for every transaction is compressed, tokenized, and exported over secure TLS connections to the log routers  154  that direct the logs to the storage cluster  156 , hosted in the appropriate geographical region, for each organization. In an embodiment, all data destined for or received from the Internet is processed through one of the enforcement nodes  150 . In another embodiment, specific data specified by each tenant, e.g., only email, only executable files, etc., is process through one of the enforcement nodes  150 . 
     Each of the enforcement nodes  150  may generate a decision vector D=[d 1 , d 2 , . . . , dn] for a content item of one or more parts C=[c 1 , c 2 , . . . , cm]. Each decision vector may identify a threat classification, e.g., clean, spyware, malware, undesirable content, innocuous, spam email, unknown, etc. For example, the output of each element of the decision vector D may be based on the output of one or more data inspection engines. In an embodiment, the threat classification may be reduced to a subset of categories, e.g., violating, non-violating, neutral, unknown. Based on the subset classification, the enforcement node  150  may allow the distribution of the content item, preclude distribution of the content item, allow distribution of the content item after a cleaning process, or perform threat detection on the content item. In an embodiment, the actions taken by one of the enforcement nodes  150  may be determinative on the threat classification of the content item and on a security policy of the tenant to which the content item is being sent from or from which the content item is being requested by. A content item is violating if, for any part C=[c 1 , c 2 , . . . , cm] of the content item, at any of the enforcement nodes  150 , any one of the data inspection engines generates an output that results in a classification of “violating.” 
     The central authority  152  hosts all customer (tenant) policy and configuration settings. It monitors the cloud and provides a central location for software and database updates and threat intelligence. Given the multi-tenant architecture, the central authority  152  is redundant and backed up in multiple different data centers. The enforcement nodes  150  establish persistent connections to the central authority  152  to download all policy configurations. When a new user connects to an enforcement node  150 , a policy request is sent to the central authority  152  through this connection. The central authority  152  then calculates the policies that apply to that user  102  and sends the policy to the enforcement node  150  as a highly compressed bitmap. 
     The policy can be tenant-specific and can include access privileges for users, websites and/or content that is disallowed, restricted domains, DLP dictionaries, etc. Once downloaded, a tenant&#39;s policy is cached until a policy change is made in the management system  120 . The policy can be tenant-specific and can include access privileges for users, websites and/or content that is disallowed, restricted domains, DLP dictionaries, etc. When this happens, all of the cached policies are purged, and the enforcement nodes  150  request the new policy when the user  102  next makes a request. In an embodiment, the enforcement node  150  exchange “heartbeats” periodically, so all enforcement nodes  150  are informed when there is a policy change. Any enforcement node  150  can then pull the change in policy when it sees a new request. 
     The cloud-based system  100  can be a private cloud, a public cloud, a combination of a private cloud and a public cloud (hybrid cloud), or the like. Cloud computing systems and methods abstract away physical servers, storage, networking, etc., and instead offer these as on-demand and elastic resources. The National Institute of Standards and Technology (NIST) provides a concise and specific definition which states cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. Cloud computing differs from the classic client-server model by providing applications from a server that are executed and managed by a client&#39;s web browser or the like, with no installed client version of an application required. Centralization gives cloud service providers complete control over the versions of the browser-based and other applications provided to clients, which removes the need for version upgrades or license management on individual client computing devices. The phrase “Software as a Service” (SaaS) is sometimes used to describe application programs offered through cloud computing. A common shorthand for a provided cloud computing service (or even an aggregation of all existing cloud services) is “the cloud.” The cloud-based system  100  is illustrated herein as an example embodiment of a cloud-based system, and other implementations are also contemplated. 
     As described herein, the terms cloud services and cloud applications may be used interchangeably. The cloud service  106  is any service made available to users on-demand via the Internet, as opposed to being provided from a company&#39;s on-premises servers. A cloud application, or cloud app, is a software program where cloud-based and local components work together. The cloud-based system  100  can be utilized to provide example cloud services, including Zscaler Internet Access (ZIA), Zscaler Private Access (ZPA), and Zscaler Digital Experience (ZDX), all from Zscaler, Inc. (the assignee and applicant of the present application). The ZIA service can provide the access control, threat prevention, and data protection described above with reference to the cloud-based system  100 . ZPA can include access control, microservice segmentation, etc. The ZDX service can provide monitoring of user experience, e.g., Quality of Experience (QoE), Quality of Service (QoS), etc., in a manner that can gain insights based on continuous, inline monitoring. For example, the ZIA service can provide a user with Internet Access, and the ZPA service can provide a user with access to enterprise resources instead of traditional Virtual Private Networks (VPNs), namely ZPA provides Zero Trust Network Access (ZTNA). Those of ordinary skill in the art will recognize various other types of cloud services  106  are also contemplated. Also, other types of cloud architectures are also contemplated, with the cloud-based system  100  presented for illustration purposes. 
     Example Server Architecture 
       FIG. 3  is a block diagram of a server  200 , which may be used in the cloud-based system  100 , in other systems, or standalone. For example, the enforcement nodes  150  and the central authority  152  may be formed as one or more of the servers  200 . The server  200  may be a digital computer that, in terms of hardware architecture, generally includes a processor  202 , input/output (I/O) interfaces  204 , a network interface  206 , a data store  208 , and memory  210 . It should be appreciated by those of ordinary skill in the art that  FIG. 3  depicts the server  200  in an oversimplified manner, and a practical embodiment may include additional components and suitably configured processing logic to support known or conventional operating features that are not described in detail herein. The components ( 202 ,  204 ,  206 ,  208 , and  210 ) are communicatively coupled via a local interface  212 . The local interface  212  may be, for example, but not limited to, one or more buses or other wired or wireless connections, as is known in the art. The local interface  212  may have additional elements, which are omitted for simplicity, such as controllers, buffers (caches), drivers, repeaters, and receivers, among many others, to enable communications. Further, the local interface  212  may include address, control, and/or data connections to enable appropriate communications among the aforementioned components. 
     The processor  202  is a hardware device for executing software instructions. The processor  202  may be any custom made or commercially available processor, a Central Processing Unit (CPU), an auxiliary processor among several processors associated with the server  200 , a semiconductor-based microprocessor (in the form of a microchip or chipset), or generally any device for executing software instructions. When the server  200  is in operation, the processor  202  is configured to execute software stored within the memory  210 , to communicate data to and from the memory  210 , and to generally control operations of the server  200  pursuant to the software instructions. The I/O interfaces  204  may be used to receive user input from and/or for providing system output to one or more devices or components. 
     The network interface  206  may be used to enable the server  200  to communicate on a network, such as the Internet  104 . The network interface  206  may include, for example, an Ethernet card or adapter or a Wireless Local Area Network (WLAN) card or adapter. The network interface  206  may include address, control, and/or data connections to enable appropriate communications on the network. A data store  208  may be used to store data. The data store  208  may include any of volatile memory elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, and the like)), nonvolatile memory elements (e.g., ROM, hard drive, tape, CDROM, and the like), and combinations thereof. 
     Moreover, the data store  208  may incorporate electronic, magnetic, optical, and/or other types of storage media. In one example, the data store  208  may be located internal to the server  200 , such as, for example, an internal hard drive connected to the local interface  212  in the server  200 . Additionally, in another embodiment, the data store  208  may be located external to the server  200  such as, for example, an external hard drive connected to the I/O interfaces  204  (e.g., SCSI or USB connection). In a further embodiment, the data store  208  may be connected to the server  200  through a network, such as, for example, a network-attached file server. 
     The memory  210  may include any of volatile memory elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, etc.)), nonvolatile memory elements (e.g., ROM, hard drive, tape, CDROM, etc.), and combinations thereof. Moreover, the memory  210  may incorporate electronic, magnetic, optical, and/or other types of storage media. Note that the memory  210  may have a distributed architecture, where various components are situated remotely from one another but can be accessed by the processor  202 . The software in memory  210  may include one or more software programs, each of which includes an ordered listing of executable instructions for implementing logical functions. The software in the memory  210  includes a suitable Operating System (O/S)  214  and one or more programs  216 . The operating system  214  essentially controls the execution of other computer programs, such as the one or more programs  216 , and provides scheduling, input-output control, file and data management, memory management, and communication control and related services. The one or more programs  216  may be configured to implement the various processes, algorithms, methods, techniques, etc. described herein. 
     Example User Device Architecture 
       FIG. 4  is a block diagram of a user device  300 , which may be used with the cloud-based system  100  or the like. Specifically, the user device  300  can form a device used by one of the users  102 , and this may include common devices such as laptops, smartphones, tablets, netbooks, personal digital assistants, MP3 players, cell phones, e-book readers, IoT devices, servers, desktops, printers, televisions, streaming media devices, and the like. The present disclosure relates to mobile devices, which are one subset of the user device  300 . The user device  300  can be a digital device that, in terms of hardware architecture, generally includes a processor  302 , I/O interfaces  304 , a network interface  306 , a data store  308 , and memory  310 . It should be appreciated by those of ordinary skill in the art that  FIG. 4  depicts the user device  300  in an oversimplified manner, and a practical embodiment may include additional components and suitably configured processing logic to support known or conventional operating features that are not described in detail herein. The components ( 302 ,  304 ,  306 ,  308 , and  302 ) are communicatively coupled via a local interface  312 . The local interface  312  can be, for example, but not limited to, one or more buses or other wired or wireless connections, as is known in the art. The local interface  312  can have additional elements, which are omitted for simplicity, such as controllers, buffers (caches), drivers, repeaters, and receivers, among many others, to enable communications. Further, the local interface  312  may include address, control, and/or data connections to enable appropriate communications among the aforementioned components. 
     The processor  302  is a hardware device for executing software instructions. The processor  302  can be any custom made or commercially available processor, a CPU, an auxiliary processor among several processors associated with the user device  300 , a semiconductor-based microprocessor (in the form of a microchip or chipset), or generally any device for executing software instructions. When the user device  300  is in operation, the processor  302  is configured to execute software stored within the memory  310 , to communicate data to and from the memory  310 , and to generally control operations of the user device  300  pursuant to the software instructions. In an embodiment, the processor  302  may include a mobile-optimized processor such as optimized for power consumption and mobile applications. The I/O interfaces  304  can be used to receive user input from and/or for providing system output. User input can be provided via, for example, a keypad, a touch screen, a scroll ball, a scroll bar, buttons, a barcode scanner, and the like. System output can be provided via a display device such as a Liquid Crystal Display (LCD), touch screen, and the like. 
     The network interface  306  enables wireless communication to an external access device or network. Any number of suitable wireless data communication protocols, techniques, or methodologies can be supported by the network interface  306 , including any protocols for wireless communication. The data store  308  may be used to store data. The data store  308  may include any of volatile memory elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, and the like)), nonvolatile memory elements (e.g., ROM, hard drive, tape, CDROM, and the like), and combinations thereof. Moreover, the data store  308  may incorporate electronic, magnetic, optical, and/or other types of storage media. 
     The memory  310  may include any of volatile memory elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, etc.)), nonvolatile memory elements (e.g., ROM, hard drive, etc.), and combinations thereof. Moreover, the memory  310  may incorporate electronic, magnetic, optical, and/or other types of storage media. Note that the memory  310  may have a distributed architecture, where various components are situated remotely from one another but can be accessed by the processor  302 . The software in memory  310  can include one or more software programs, each of which includes an ordered listing of executable instructions for implementing logical functions. In the example of  FIG. 3 , the software in the memory  310  includes a suitable operating system  314  and programs  316 . The operating system  314  essentially controls the execution of other computer programs and provides scheduling, input-output control, file and data management, memory management, and communication control and related services. The programs  316  may include various applications, add-ons, etc. configured to provide end-user functionality with the user device  300 . For example, example programs  316  may include, but not limited to, a web browser, social networking applications, streaming media applications, games, mapping and location applications, electronic mail applications, financial applications, and the like. In a typical example, the end-user typically uses one or more of the programs  316  along with a network such as the cloud-based system  100 . 
     User Device Application for Traffic Forwarding and Monitoring 
       FIG. 5  is a network diagram of the cloud-based system  100  illustrating an application  350  on user devices  300  with users  102  configured to operate through the cloud-based system  100 . Different types of user devices  300  are proliferating, including Bring Your Own Device (BYOD) as well as IT-managed devices. The conventional approach for a user device  300  to operate with the cloud-based system  100  as well as for accessing enterprise resources includes complex policies, VPNs, poor user experience, etc. The application  350  can automatically forward user traffic with the cloud-based system  100  as well as ensuring that security and access policies are enforced, regardless of device, location, operating system, or application. The application  350  automatically determines if a user  102  is looking to access the open Internet  104 , a SaaS app, or an internal app running in public, private, or the datacenter and routes mobile traffic through the cloud-based system  100 . The application  350  can support various cloud services, including ZIA, ZPA, ZDX, etc., allowing the best in class security with zero trust access to internal apps. For example, the application  350  can be referred to as a “client connector,” enabling the user device  300  to connect to cloud services. 
     The application  350  is configured to auto-route traffic for a seamless user experience. This can be protocol as well as application-specific, and the application  350  can route traffic with a nearest or best fit enforcement node  150 . Further, the application  350  can detect trusted networks, allowed applications, etc. and support secure network access. The application  350  can also support the enrollment of the user device  300  prior to accessing applications. The application  350  can uniquely detect the users  102  based on fingerprinting the user device  300 , using criteria like device model, platform, operating system, etc. The application  350  can support Mobile Device Management (MDM) functions, allowing IT personnel to deploy and manage the user devices  300  seamlessly. This can also include the automatic installation of client and SSL certificates during enrollment. Finally, the application  350  provides visibility into device and app usage of the user  102  of the user device  300 . 
     The application  350  supports a secure, lightweight tunnel between the user device  300  and the cloud-based system  100 . For example, the lightweight tunnel can be HTTP-based. With the application  350 , there is no requirement for PAC files, an IPSec VPN, authentication cookies, or end user  102  setup. 
     Zero Trust Network Access Using the Cloud-Based System 
       FIG. 6  is a network diagram of a Zero Trust Network Access (ZTNA) application utilizing the cloud-based system  100 . For ZTNA, the cloud-based system  100  can dynamically create a connection through a secure tunnel between an endpoint (e.g., users  102 A,  102 B) that are remote and an on-premises connector  400  that is either located in cloud file shares and applications  402  and/or in an enterprise network  404 , connected to enterprise file shares and applications. The connection between the cloud-based system  100  and on-premises connector  400  is dynamic, on-demand, and orchestrated by the cloud-based system  100 . A key feature is its security at the edge—there is no need to punch any holes in the existing on-premises firewall. The connector  400  inside the enterprise (on-premises) “dials out” and connects to the cloud-based system  100  as if too were an endpoint. This on-demand dial-out capability and tunneling authenticated traffic back to the enterprise is a key differentiator for ZTNA. Also, this functionality can be implemented in part by the application  350  on the user device  300 . The connector  400  can be referred to as a “service edge.” 
     The paradigm of virtual private access systems and methods is to give users network access to get to an application and/or file share, not to the entire network. If a user is not authorized to get the application, the user should not be able even to see that it exists, much less access it. The virtual private access systems and methods provide an approach to deliver secure access by decoupling applications  402  from the network  404 , instead of providing access with a connector  400 , in front of the applications  402 , an application on the user device  300 , a central authority  152  to push policy  410 , and the cloud-based system  100  to stitch the applications  402  and the software connectors  400  together, on a per-user, per-application basis. 
     With the virtual private access, users can only see the specific applications  402  allowed by the policy  410 . Everything else is “invisible” or “dark” to them. Because the virtual private access separates the application from the network, the physical location of the application  402  becomes irrelevant—if applications  402  are located in more than one place, the user is automatically directed to the instance that will give them the best performance. The virtual private access also dramatically reduces configuration complexity, such as policies/firewalls in the data centers. Enterprises can, for example, move applications to Amazon Web Services or Microsoft Azure, and take advantage of the elasticity of the cloud, making private, internal applications behave just like the marketing leading enterprise applications. Advantageously, there is no hardware to buy or deploy, because the virtual private access is a service offering to end-users and enterprises.  FIG. 5  can include the ZPA service from Zscaler, Inc. 
     Digital Experience Monitoring 
       FIG. 7  is a network diagram of the cloud-based system  100  in an application of digital experience monitoring. Here, the cloud-based system  100  providing security as a service as well as ZTNA, can also be used to provide real-time, continuous digital experience monitoring, as opposed to conventional approaches (synthetic probes). A key aspect of the architecture of the cloud-based system  100  is the inline monitoring. This means data is accessible in real-time for individual users from end-to-end. As described herein, digital experience monitoring can include monitoring, analyzing, and improving the digital user experience. 
     The cloud-based system  100  connects users  102  at the locations  110 ,  112 ,  118  to the applications  402 , the Internet  104 , the cloud services  106 , etc. The inline, end-to-end visibility of all users enables digital experience monitoring. The cloud-based system  100  can monitor, diagnose, generate alerts, and perform remedial actions with respect to network endpoints, network components, network links, etc. The network endpoints can include servers, virtual machines, containers, storage systems, or anything with an IP address, including the Internet of Things (IoT), cloud, and wireless endpoints. With these components, these network endpoints can be monitored directly in combination with a network perspective. Thus, the cloud-based system  100  provides a unique architecture that can enable digital experience monitoring, network application monitoring, infrastructure component interactions, etc. Of note, these various monitoring aspects require no additional components—the cloud-based system  100  leverages the existing infrastructure to provide this service. 
     Again, digital experience monitoring includes the capture of data about how end-to-end application availability, latency, and quality appear to the end user from a network perspective. This is limited to the network traffic visibility and not within components, such as what application performance monitoring can accomplish. Networked application monitoring provides the speed and overall quality of networked application delivery to the user in support of key business activities. Infrastructure component interactions include a focus on infrastructure components as they interact via the network, as well as the network delivery of services or applications. This includes the ability to provide network path analytics. 
     The cloud-based system  100  can enable real-time performance and behaviors for troubleshooting in the current state of the environment, historical performance and behaviors to understand what occurred or what is trending over time, predictive behaviors by leveraging analytics technologies to distill and create actionable items from the large dataset collected across the various data sources, and the like. The cloud-based system  100  includes the ability to directly ingest any of the following data sources network device-generated health data, network device-generated traffic data, including flow-based data sources inclusive of NetFlow and IPFIX, raw network packet analysis to identify application types and performance characteristics, HTTP request metrics, etc. The cloud-based system  100  can operate at 10 gigabits ( 10 G) Ethernet and higher at full line rate and support a rate of 100,000 or more flows per second or higher. 
     The applications  402  can include enterprise applications, Office  365 , Salesforce, Skype, Google apps, internal applications, etc. These are critical business applications where user experience is important. The objective here is to collect various data points so that user experience can be quantified for a particular user, at a particular time, for purposes of analyzing the experience as well as improving the experience. In an embodiment, the monitored data can be from different categories, including application-related, network-related, device-related (also can be referred to as endpoint-related), protocol-related, etc. Data can be collected at the application  350  or the cloud edge to quantify user experience for specific applications, i.e., the application-related and device-related data. The cloud-based system  100  can further collect the network-related and the protocol-related data (e.g., Domain Name System (DNS) response time). 
     Application-Related Data 
     
       
         
           
               
               
             
               
                   
               
             
            
               
                 Page Load Time 
                 Redirect count (#) 
               
               
                 Page Response Time 
                 Throughput (bps) 
               
               
                 Document Object Model (DOM) 
                 Total size (bytes) 
               
               
                 Load Time 
               
               
                 Total Downloaded bytes 
                 Page error count (#) 
               
               
                 App availability (%) 
                 Page element count by category (#) 
               
               
                   
               
            
           
         
       
     
     Network-Related Data 
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 HTTP Request metrics 
                 Bandwidth 
               
               
                   
                 Server response time 
                 Jitter 
               
               
                   
                 Ping packet loss (%) 
                 Trace Route 
               
               
                   
                 Ping round trip 
                 DNS lookup trace 
               
               
                   
                 Packet loss (%) 
                 GRE/IPSec tunnel monitoring 
               
               
                   
                 Latency 
                 MTU and bandwidth measurements 
               
               
                   
                   
               
            
           
         
       
     
     Device-Related Data (Endpoint-Related Data) 
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 System details 
                 Network (config) 
               
               
                   
                 Central Processing Unit (CPU) 
                 Disk 
               
               
                   
                 Memory (RAM) 
                 Processes 
               
               
                   
                 Network (interfaces) 
                 Applications 
               
               
                   
                   
               
            
           
         
       
     
     Metrics could be combined. For example, device health can be based on a combination of CPU, memory, etc. Network health could be a combination of Wi-Fi/LAN connection health, latency, etc. Application health could be a combination of response time, page loads, etc. The cloud-based system  100  can generate service health as a combination of CPU, memory, and the load time of the service while processing a user&#39;s request. The network health could be based on the number of network path(s), latency, packet loss, etc. 
     The lightweight connector  400  can also generate similar metrics for the applications  402 . In an embodiment, the metrics can be collected while a user is accessing specific applications that user experience is desired for monitoring. In another embodiment, the metrics can be enriched by triggering synthetic measurements in the context of an inline transaction by the application  350  or cloud edge. The metrics can be tagged with metadata (user, time, app, etc.) and sent to a logging and analytics service for aggregation, analysis, and reporting. Further, network administrators can get UEX reports from the cloud-based system  100 . Due to the inline nature and the fact the cloud-based system  100  is an overlay (in-between users and services/applications), the cloud-based system  100  enables the ability to capture user experience metric data continuously and to log such data historically. As such, a network administrator can have a long-term detailed view of the network and associated user experience. 
     Unified Agent Application 
       FIG. 8  is a network diagram of the use of the application  350  as a unified agent application and associated connectivity and functionality with the cloud-based system  100 , i.e., a “client connector.” Again, the unified agent application  350  is executed on a user device  300 . The unified agent application  350  dynamically learns all available services, adapts to changing network environments, and provides a seamless and secure network resource access to Internet and darknet hosted applications. This is achieved through dynamic evaluation of network conditions, enrollment to individual services, learning individual service protocols, creating a link-local network on the user device  300 , and establishing multiple secure tunnels to cloud services over this local network. 
     The unified agent application  350  is communicatively coupled to an agent manager cloud  606 , as well as the cloud-based system  100 . The unified agent application  350  enables communication to enterprise private resources on the enterprise network  404  via the cloud-based system  100  and to the Internet  104  via the cloud-based system  100 . The agent manager cloud  606  can communicate with enterprise asset management  614 , an enterprise Security Assertion Markup Language (SAML) Identity Provider (IDP)  616 , and an enterprise Certificate Authority (CA)  618 . The user device  300  and the unified agent application  350  can perform a registration/identity  620  process through the agent manager cloud  606  where the user identity, the user&#39;s certificates, and a device fingerprint can uniquely identify the user device  300 . Once registered, the unified agent application  350  has an identity  622 , which can include the user, certificates, device posture, etc. and which is shared with the cloud-based system  100 . 
     The unified agent application  350  operates on a client-server model where an IT admin enables appropriate services for end users at a Cloud Administration Server (CAS), which can be part of the agent manager cloud  606 , namely the enterprise asset management  614 . Every client can make a unicast request to the agent manager cloud  606  (e.g., CAS) to discover all enabled services. On acknowledging the response, the client issues a request to authenticate to each service&#39;s cloud Identity Providers, the enterprise SAML IDP  616 . Authentication can be multi-factor depending upon the nature of the service. On successful authentication, server contacts Mobile Device Management (MDM) or Inventory management provider to define access control rights for the user device  300 . Post authorization, the user device  300  is successfully enrolled in the agent manager cloud  606 , which tracks and monitors all behavior of the user device  300 . 
     Post-enrollment, the user device  300  creates a link local network with a specific IP configuration, opens a virtual network interface to read and write packets to create secure tunnels to available services through the cloud-based system  100 . On network changes, the user device  300  dynamically evaluates reachability to pre-configured domains and depending upon the result, it appropriately transitions all network tunnels, thus providing a seamless experience to the end user. Further, the user device  300  also intelligently learns the conditions which are appropriate for setting up network tunnels to cloud services depending upon several network heuristics such as reachability to a particular cloud service. 
     Unified Agent Application—Functionality 
     Generally, the unified agent application  350  supports two broad functional categories—1) dynamic service discovery and access controls and 2) service availability. The dynamic service discovery and access controls include service configuration by the administrator, service discovery by the user device  300 , service acknowledgment and authentication, service authorization and enrollment, and the like. For service configuration by the administrator, the IT admin can provide cloud service details at a centralized knowledge server, such as part of the agent manager cloud  606 , the enterprise asset management  614 , etc. The cloud service details include the service type (e.g., Internet/intranet), network protocol, identity provider, server address, port, and access controls, etc. 
     For service discovery by the user device  300 , the user device  300  can issue a network request to a known Cloud Administrative Server (CAS) in the agent manager cloud  606  to discover all enabled services for a user. If a specific cloud server is not known a priori, the user device  300  can broadcast the request to multiple clouds, e.g., through the agent manager cloud  606  communicating to the enterprise asset management  614 , the enterprise SAML IDP  616 , and the enterprise CA  618 . 
     For the service acknowledgment and authentication, the user device  300  acknowledges the response of service discovery and initiates the authentication flow. The user device  300  learns the authentication protocol through the service discovery configuration and performs authentication of a configured nature at the enterprise SAML IDP  616 . For the service authorization and enrollment, post successful authentication, the CAS, authorizes the user device  300 , and fetches the access control information by contacting an MDM/Inventory Solutions Provider. Depending upon the user context and the nature of access, the CAS enrolls the user device  300  into several cloud services and informs the cloud services that the user has been enrolled for access. 
     The service availability includes link local network setup, a traffic interceptor, and dynamic traffic forwarding tunnels to authorized services. The link-local network setup, post-enrollment, has the user device  300  create a local network on the user device  300  itself to manage various networking functionalities. For the traffic interceptor, the user device  300  intercepts and evaluates all Internet traffic. Allowed traffic is tunneled to the cloud services such as in the cloud-based system  100 , whereas the rest of the traffic is denied as per enterprise policies. For the dynamic traffic forwarding tunnels to authorized services, depending upon the evaluation, the user device  300  splits the traffic into the different tunnel to individual cloud services such as in the cloud-based system  100 . 
     The unified agent application  350  is a single application that provides secure connectivity to the Internet  104  and darknet hosted applications, such as the enterprise private resources in the enterprise network  404 . The unified agent application  350  communicates securely to the agent manager cloud  606 , which is controlled by an IT admin. The unified agent application  350  learns available services and authenticates with each service. Post proper enrollment, the unified agent application  350  securely connects to cloud services by means of network tunnels. 
     Unified Agent Application—Workflow 
       FIG. 9  is a network diagram of the example workflow of the unified agent application  350 . The user device  300  again executes the unified agent application  350 , as well as a browser  630  (or some other application requesting network services). First, the user device  300  includes authentication through an application portal  632  and download/install of the unified agent application  350  therefrom (step  640 - 1 ). Note, the application portal  632  can be a website, Apple&#39;s app store, Google Play, Windows Store, etc. Once installed, the unified agent application  350  communicates to the agent manager cloud  606  communicating identity and asking for available services (“I am User X, what are my services?”) and the agent manager cloud  606  responds with the available services (“You have Z services”) (step  640 - 2 ). 
     Next, the unified agent application  350  includes authentication using a VPN Service Provider (SP) with the cloud-based system  100  (step  640 - 3 ). The unified agent application  350  next enrolls the user device  300  through the agent manager cloud  606  (step  640 - 4 ). The agent manager cloud  606  performs a device asset policy check with the enterprise asset management  614  (step  640 - 5 ). The agent manager cloud  606 , upon the successful check, provides the unified agent application  350  an affirmative response (step  640 - 6 ). The unified agent application  350  sends a Certificate Signing Request (CSR) to the agent manager cloud  606  (step  640 - 7 ), and the agent manager cloud  606  sends the CSR request to the enterprise CA, and the certificate is returned to the unified agent application  350  (step  640 - 8 ). Finally, the unified agent application  350  enables VPN connectivity to the cloud-based system  100  (step  640 - 9 ). 
       FIG. 10  is a flow diagram of an event sequence associated with the unified agent application  350 . The event sequence is shown between the user device  300  executing the unified agent application  350 , a mobile admin function  650  such as implemented through the agent manager cloud  606 , an enforcement node  150 , a VPN node  652  such as through the cloud-based system  100 , an MDM function  654  such as through the enterprise asset management  614 , and an IDP function  656  such as through the enterprise SAML IDP  616 . The user device  300  discovers services with the mobile admin function  650  (step  660 ), and the user device  300  is authenticated by the IDP function  656  (step  662 ). The user device  300  enrolls in discovered services through the mobile admin function  650  (step  664 ). 
     The mobile admin function  650  is configured to authorize the services with the MDM function  654  (step  666 ), enroll in the services through the VPN node  652  (step  668 ), and the enforcement nodes  150  (step  670 ). A success/error is provided by the mobile admin function  650  to the user device  300 . Subsequently, the user device  300 , through the unified agent application  350 , accesses the services such as a secure tunnel for internet access through the enforcement nodes  150  (step  674 ) or a secure tunnel for intranet access through the VPN node  652  (step  676 ). 
     Unified Agent Application—Architecture 
       FIG. 11  is a logical diagram of the functional components of the unified agent application  350 . The unified agent application  350  is configured to operate on the mobile user device  300 . The cloud-based system  100  can provide Internet security as well as cloud-based remote access to enterprise internal resources through a VPN. These cloud services are designed and well suited for road warriors. Road warriors are the users who are accessing the Internet  104  and enterprise internal services from outside the corporate physical network perimeter. These are the users  102  who are accessing the Internet  104  and Enterprise resources from home, airports, coffee shops, and other external unsecured hotspots. 
     The unified agent application  350  provides authenticated and encrypted tunnels from road warrior devices  300  and, in some use cases, it even needs to be enforceable so that end users cannot disable the unified agent application  350 . The VPN, which is the remote access service, also needs authenticated and encrypted tunnel from road warrior user devices  300 . Both of these solutions also need to provide feedback to the end user in the event that access was blocked due to security or compliance reasons. The following describes the architecture and design of the unified agent application  350 , including an endpoint client architecture, backend changes, auto-update, and integration with the cloud-based system  100 . 
     The unified agent application  350  includes logical components including view components  702 , business processes and services  704 , data  706 , and cross-cutting functions  708 . The view components  702  include User Interface (UI) components  710  and UI process components  712 . The business processes and services  704  include a tray user process  714 , a helper user process  716 , a tunnel system service  718 , a posture system service  720 , and an updater system service  722 . The data  706  includes encrypted data  724 , configuration data  726 , and logs  728 . The cross-cutting functions  708  are across the view components  702 , the business processes and services  704 , and the data  706  and include security  730 , logging  732 , and statistics  734 . 
     The unified agent application  350  has a useful goal of simplified provisioning of the proxy (for security through the cloud-based system  100  to the Internet  104 ) and the VPN (for access through the cloud-based system  100  to the enterprise private resources in the enterprise network  404 ). That is, the unified agent application  350  allows the use of the cloud-based system  100  as a proxy for Internet-bound communications. The unified agent application  350  further allows the use of the cloud-based system  100  as a tunnel for Intranet-bound communications to the enterprise private resources. With the unified agent application  350  setting up a local network at the user device  300 , the unified agent application  350  can manage communications between the Internet and the intranet, i.e., two of the main categories of cloud services—proxy to the Internet and tunnel to the intranet. The unified agent application  350  further has objectives of simplified user enrollment in the proxy and tunnels. 
     In an embodiment, the unified agent application  350  is a native application. The common functionality is abstracted out and made into common libraries based on C or C++ so that it can be reused across different platforms (e.g., iOS, Android, etc.). Example functionality: Traffic forwarding tunnels, local proxy, authentication backend, logging, statistics, etc. The UI components  710  and UI process components  712  can be platform dependent. Also, the unified agent application  350  is designed and implementable such that other third-party VPN applications, if configured by the enterprise, can be used concurrently. 
     The app portal  632  enables the installation of the unified agent application  350  on the user device  300 . For example, an admin may be able to push and install the unified agent application  350  to the user device  300  using remote-push mechanisms like GPO, MDMs, etc. Additionally, the user can download the unified agent application  350  if they have access to the installation file and install it on their own. The unified agent application  350  supports automatic updates without impacting the user&#39;s Internet experience. If a problem is encountered, then it should roll back to the previously successful state or fail open. The unified agent application  350  can have a security check to ensure that it is not tampered and updated from the right source with a hash match with a source hash when upgrading. 
     The user can log into the unified agent application  350 . Once the user sends their User ID through the unified agent application  350  to the agent manager cloud  606 , the cloud-based system  100 , and/or the app portal  632 , the app portal  632  can determine the company&#39;s authentication mechanism, such as through a lookup in the enterprise asset management  614 , and validate password through the enterprise CA  618 . 
     Through the unified agent application  350 , a user can be authenticated to the proxy or the VPN through the cloud-based system  100 . For authentication of the user to the proxy, using SAML, the user can log into the unified agent application  350  by using their user ID and transparent SAML authentication thereafter, including SAML certificate. The app portal  632  shall determine that an organization is using SAML for authentication through the enterprise CA  618  and redirect to the enterprise SAML IDP  616  to get SAML assertion and use it to authenticate the user. 
     For authentication of the user to the tunnel, using SAML, the user can log into the unified agent application  350  by just using their user ID and based on the user ID, the unified agent application  350  shall redirect the user for authentication to enterprise SAML IDP  616  and SAML assertion shall be sent. The VPN service shall validate SAML assertion; if the assertion is valid, then the unified agent application  350  shall collect hardware parameters like device serial number, model number, etc. and create CSR. The CSR shall be signed by the enterprise CA  618 , and the certificate shall be pushed to the unified agent application  350 . The unified agent application  350  shall install the certificate to KMS/keychain and save assertion. 
     After the user has been successfully authenticated, the user shall be enrolled in the proxy service, and the user&#39;s traffic forwarding profile shall be downloaded from unified agent application  350 , including Secure Sockets Layer (SSL) certificates and exceptions. The unified agent application  350  shall indicate that the user is connected to cloud-based system  100 , and app statistics shall be populated. 
     After the user has successfully authenticated (including transparent authentication), the user shall be enrolled with a VPN service, and the VPN broker info shall be downloaded by the unified agent application  350 , and the VPN tunnel shall be established. The unified agent application  350  can support captive portal detection to fail open when users are behind a captive portal to allow connection to a captive portal. 
     The unified agent application  350  can forward internal enterprise traffic from the user device  300  to the VPN. The unified agent application  350  can recognize when a user goes to an internal app that is provisioned with the VPN service. The unified agent application  350  shall auto-enable a tunnel to the VPN service when the user tries connecting to an internal app. The proxy service can always be enforced, and the user is not able to remove it by switching off tunnel or removing the unified agent application  350 . Without the proxy solution enforced, the user is not able to access the Internet and would be prompted to restart the web security service, via the unified agent application  350 . 
     The VPN is an on-demand service, unlike the proxy service that shall be enforceable by default so that the user can enable/disable the VPN at will without any password requirements. Once the user logs into the VPN service using a ‘Connect,’ the same button shall be labeled ‘Disconnect,’ and the user shall be able to disconnect the VPN service with a single click. Every time user disconnects with VPN service. The VPN service can be auto-disabled if the user puts their system to sleep mode or there is inactivity (no packets exchanged) after x minutes (x shall be configurable in the VPN settings). 
     The admin can turn off the proxy service with a single client from an admin UI for a user, all users, or some subset of users. This does not remove the unified agent application  350  from the user device  300 . A user may be able to disable the proxy service, provided they have the authority and credentials. The unified agent application  350  can provide service-related notifications to the user. For example, the unified agent application  350  can provide notifications such as push alerts or the like as well as contain a notification area for a single place to show all notifications that are generated by the proxy service and the VPN service. This shall also include app notifications, including configuration updates, agent updates, etc. The user shall be able to clear notifications as well as filter notifications from this screen. This shall include a filter for VPN/Proxy, blocked, cautioned, quarantine actions. 
     Unified Agent Application—User Workflow 
     Again, the unified agent application  350  is executed on the user device  300 . For authentication, the user enters a User ID in the unified agent application  350 , such as userid@domain. Subsequently, the unified agent application  350  is configured to discover the services enabled—proxy service and VPN services based on userid@domain. The user authenticates with the presented services, i.e., proxy service, VPN services, and combinations thereof. The unified agent application  350  is auto-provisioned for the authenticated service by downloading the service-specific configuration. The unified agent application  350  performs the following during VPN enrollment—get the User/Device certificate signed by an Enterprise Intermediate Certificate. This Intermediate Certificate will be the same, which will be used for signing Assistants. The unified agent application  350  also will pin hardware signatures/fingerprints to the certificate and user, e.g., Storage Serial ID (Hard Drive Serial ID), CPU ID, Mother Board Serial ID, BIOS serial number, etc. 
     Unified Agent Application—Authentication and Enrollment Protocol 
       FIG. 12  is a flowchart of a proxy authentication process  750  to the cloud-based system  100 . For authentication in the proxy service, conventionally, devices  300  can use proxy authentication to register to the cloud-based system  100 . This is not truly reliable as it depends on location/location-authentication policy/VPN and other such factors to work correctly. To simplify this flow, the following new flow can be used with the unified agent application  350  for the process  750 . First, the mobile client user device  300  initiates an HTTPS request to a CA (e.g., the enterprise CA  618 ) (step  752 ). For example, this can be as follows: 
     login.zscaler.net/clstart?version=1&amp;_domain=nestle.com&amp;redrurl=&lt;url-encoded-url-with-schema&gt;
 
If the domain is invalid or if the redrurl is missing, CA will reset the connection.
 
     The above endpoint begins the client auth flow (step  754 ). The provided domain is the company that requires the auth. The CA looks up the domain to find the company and their auth mechanism. If the company uses hosted or Active Directory (AD)/Lightweight Directory Access Protocol (LDAP) authentication [SAML auth flow starts at step  760 ], the response will be a login form with input fields for [username] &amp; [password] (step  756 ). The form is submitted via POST to the CA at a below endpoint: 
     
       
         
           
               
             
               
                   
               
             
            
               
                 https://login.zscaler.net/clicred. The HTTP content may look like below 
               
               
                 POST /clicred 
               
               
                 Host: login.zscaler.net 
               
               
                 Content-Length: xyz 
               
               
                 username=xyz@nestle.com&amp;password=123456&amp;redrurl=&lt;url-encoded- 
               
               
                 posturl-with-schema&gt; 
               
               
                   
               
            
           
         
       
     
     Next, the CA performs user/password validation and responds with a message (step  758 ). If the company uses SAML, the response to the request in step  752  will be the SAMLRequest form. The SAMLRequest form will auto-submit to the IDP. Once auth completes, the CA gets control back with the identity of the user. Once SAMLResponse comes back, send the response as a  307  redirect to redrurl (step  762 ) with a below format 
     
       
         
           
               
               
             
               
                   
                   
               
             
            
               
                   
                 Location: zsa://auth[?token=encrypted-cookie&amp;...] to be appended. 
               
               
                   
                 307 query params 
               
               
                   
                 ---------------- 
               
               
                   
                 token= (on success) 
               
               
                   
                 ecode= (on error) 
               
               
                   
                 emsg= (on error) 
               
               
                   
                 On error, send the same redrurl with below format 
               
               
                   
                 zsa://auth?ecode=&lt;code&gt;&amp;emsg=&lt;message&gt; 
               
               
                   
                   
               
            
           
         
       
     
       FIG. 13  is a flowchart of a VPN authentication process  780  to the cloud-based system  100 . The client (user device  300 ) issues a GET web request to the VPN authentication server with the domain name as the query parameter (step  782 ), such as: 
     GET //&lt;auth-server&gt;?domain=mockcompany.com
 
The server identifies the IDP for the given domain and responds with a Hypertext Markup Language (HTML) page containing a SAML Request (step  784 ). The client will redirect to the IDP with the SAML Request (step  786 ). The IDP will challenge the client for credentials, which can be of the form of a username/password or client identity certificate (step  788 ). On successful authentication, IDP will generate a SAMLResponse for the VPN authentication server (step  790 ). The client will record the SAMLAssertion for future tunnel negotiation. In the case of error, the server will resend the challenge to the user (step  792 ).
 
       FIG. 14  is a flowchart of a device enrollment process  800  for the client user device  300  and the unified agent application  350 . Post successful authentication with all services, in this case, the proxy services, and the VPN services, the client sends an enrollment request to mobile admin (Cloud Administrative Server CAS) (step  802 ). The request contains a device fingerprint and an authentication context for each service to identify the user (step  804 ). For example, the cloud-based system  100  can use cookies, and the VPN can use SAMLAssertion for the authentication context. The mobile admin (agent manager cloud  606 ) performs inventory lookup with device fingerprints at the MDM server to authorize the user and the user device  300  (step  806 ). On successful authorization, the mobile admin server enrolls the user to cloud services with their authentication contexts (step  808 ). Each cloud service responds with specific access controls and protocol information that the client receives from mobile admin and uses for local network setup (step  810 ). 
     Unified Agent Application—Traffic Interception and Splitting 
     Again, to protect Internet-bound traffic and simultaneously access enterprise-specific Intranet traffic, the user device  300  needs to connect through multiple applications. Again, it is not straightforward for users to configure these applications in different networks, and different VPN and proxy solutions arise compatibility issues when operating simultaneously. The unified agent application  350  is designed to solve all these issues. The unified agent application  350  handles both proxy (Internet-bound) traffic, and Enterprise Intranet bound traffic. The unified agent application  350  provides secure access to Organizational internal resources when the user is outside of the enterprise network. For Internet-bound traffic, it will forward traffic to the enforcement node  150 , and for intranet bound traffic, it will forward traffic to a VPN (Broker) or direct if the user is inside the organization network. 
     The unified agent application  350  is configured to intercept all traffic, specifically to intercept all Transmission Control Protocol (TCP) traffic and DNS traffic before it goes out through the external network interface in the user device  300 . The unified agent application  350  can intercept other types of traffic as well, such as the User Datagram Protocol (UDP). The unified agent application  350  is configured to split traffic at the user device  300 , i.e., based on a local network configured at the user device  300 . Split traffic based upon port, protocol, and destination IP. The unified agent application  350  is configured to send VPN traffic direct for trusted networks (organization&#39;s internal network). The unified agent application  350  can also coexist with other VPN clients, i.e., it does not intercept the traffic targeted for those interfaces by specific routes. 
     Thus, the unified agent application  350  is configured to intercept all traffic at the IP layer for the device  300  or other VPN client&#39;s default route. Then, the unified agent application  350  is configured to split traffic. Based upon port, protocol, and destination IP as configured by the IT administrator 
       FIG. 15  is a flowchart of a traffic interception process  820  implemented through the unified agent application  350 . The unified agent application  350  registers and sets up a new Network Adapter (TUN interface) on the device (step  822 ). The unified agent application  350  overrides the device&#39;s network default route by configuring the default route of higher priority for the TUN interface (step  824 ). The unified agent application  350  sets a specific route (exact match) for all DNS servers configured on the user device  300  with the highest priority (step  826 ). The unified agent application  350  will not override other specific routes of an external adapter or other VPN clients (step  828 ). 
     For each IP packet coming to the TUN interface, packet processing is performed (step  830 ). The application does a &lt;port, protocol, destination-IP&gt; lookup on every IP packet and sends it on one of the dedicated tunnels based upon configured rules of packet transport. 
       FIG. 16  is a flow diagram of traffic interception and splitting  850  using the unified agent application  350 . Again, the unified agent application  350  creates and operates a tunnel (TUN) interface  852  on the user device  300 . The user device  300  includes one or more client applications  854 , which can be any program or service executable on the user device  300 , which requires access to the network interface on the user device  300 . Traffic for the default route from the client applications  854  is sent to the TUN interface  852 , but traffic for specific routes can be sent to other interfaces  856 , separate from the TUN interface, for direct connectivity to the Internet  504 , such as via VPN services or direct. 
     The TUN interface  852  splits  858  all traffic. TCP traffic for internal domains is sent to a VPN/broker server  860 , TCP port 80/443 traffic is sent to the cloud-based system  100  for a proxy such as to the enforcement node  150 . Finally, other traffic can be sent directly to the Internet  504 . In this manner, the TUN interface  852  operates a local network at the user device  300 . 
       FIG. 17  is a flow diagram of tunnel forwarding rules  940  by the unified agent application  350 . A periodic health monitor function  942  operates, based on a periodic timer  944 , to check a PAC ping and a gateway connect ping to provide a state to a bypass fail/open module  946 . A network state change function  948  is configured to detect a network change event  950  such as DNS server address, DNS search domains, on-net host DNS lookups, etc., and to provide a state to the bypass fail/open module  946 . The bypass fail/open module  946  creates an active tunnel  952  or disabled tunnel  954  based on the states. 
     Service Driven Split Tunneling 
       FIG. 18  is a flowchart of a service driven split tunneling process  1000 . The service driven split tunneling process  1000  provides better scalability, security, and segmentation of traffic in mobile and cloud environments. The service driven split tunneling process  1000  can include the traffic interception and splitting  850  using the unified agent application  350 . Again, as illustrated in  FIG. 18 , the unified agent application  350  creates and operates a tunnel (TUN) interface  852  on the mobile user device  300 . The mobile user device  300  includes one or more client applications  854 , which can be any program or service executable on the user device  300 , which requires access to the network interface on the user device  300 . Traffic for the default route from the client applications  854  is sent to the TUN interface  852 , but traffic for specific routes can be sent to other interfaces  856 , separate from the TUN interface, for direct connectivity to the Internet  504 , such as via VPN services or direct. 
     The service driven split tunneling process  1000  includes a mobile application/agent which is installed on a mobile device for packet interception (step  1002 ). For example, the mobile application/agent can be the unified agent application  350  on the mobile user device  300 . The mobile application/agent can inject a default route on the mobile device pointing to its own interface to get all Layer  2  or Layer  3  packets. 
     The mobile application/agent is configured with a set of rules (step  1004 ). The set of rules can be learned at runtime (as the mobile application/agent operates, configured at application launch, configured during application operation, and a combination thereof. For example, the set of rules can be configured by IT administrators for specific users, groups, departments, etc. and sent to the mobile application/agent. Further, the set of rules can be learned based on the operation of the mobile application/agent. 
     The set of rules can be an array of tuples of included and excluded traffic. For example, the array of tuples can include the following format 
     &lt;exclude, destination_port, protocol, destination_IP address_subnet&gt; 
     &lt;include, destination_port, protocol, destination_IP address_subnet, transport_type&gt; 
     For example, a set of rules can include 
     &lt;include, 443, TCP, 17.0.0.0/8, &lt;TCP, gateway.zscaler.net:80 
     This rule would tunnel all TCP port 443 traffic destined to 17.0.0.0/8 subnet over a TCP transport on port 80 to host.com. Another rule can include 
     &lt;exclude, 53, UDP, *&gt; 
     This rule does not tunnel any UDP port 53 (DNS) traffic, but rather sends it direct. 
     Based on the set of rules, the mobile application/agent opens tunnels to different host concentrators (step  1006 ). As described herein, the host concentrators can be the enforcement nodes  150 , etc. The tunnel may or may not be authenticated depending upon the requirements. For the traffic that needs to go direct, the mobile application/agent proxies the connections locally through a RAW Socket or via a custom TCP/IP Stack embedded within the application itself. 
     The mobile application/agent intercepts packets on the user device and forwards over the tunnels based on the set of rules (step  1008 ). Through this granular splitting of network traffic, IT administrators will have better control of the network traffic in terms of security and scalability. For instance, an IT admin can now control that only special traffic such as Session Initiation Protocol (SIP) should go outside the tunnel, and rest should go to some security gateway or vice versa. Any number of complex rules is hence possible. 
     End users will also have significant performance benefits over traditional SSL/IPSec VPNs where traffic of different needs compete with each other. The service driven split tunneling process  1000  allows function-driven security and on-demand scalability for different services. So, File Transfer Protocol (FTP) traffic goes to a secure FTP proxy, Web traffic (TCP, port 80 traffic) goes to a Web proxy, HTTPS (TCP, port 443) goes to an SSL acceleration proxy, SIP traffic goes to SIP traffic processing concentrator and so on. 
     Hybrid Architecture for Security Processing 
     Again, the present disclosure relates to mobile devices, which are one subset of the user device  300 , referred to herein as a mobile device  300 . The present disclosure relates to systems and methods for enforcing security policies on mobile devices  300  in a hybrid architecture. Here, the hybrid architecture means security processing occurs both via the application  350  and the cloud-based system  100  in a unified and coordinated manner. The hybrid architecture utilizes the application  350  first to generate a local decision about whether to BLOCK/ALLOW connections based on a local map. If a connection is not in the local map, the application  350  forwards a request to the cloud-based system  100  to generate a decision. In this manner, the hybrid architecture decreased bandwidth consumption between the mobile device  300  and the cloud-based system  100  by utilizing the previous BLOCK information. The hybrid architecture decreases processor utilization on the mobile device  300  by relying on a cloud service through the cloud-based system  100  for calculating request signatures, detecting malware, detecting privacy information leakage, etc. That is, the application  350  makes simple decisions—ALLOW or BLOCK, and the cloud-based system  100  does advanced processing where needed, sandbox, advanced threat detection, signature-based detection, DLP dictionary analysis, etc. 
     This approach also decreases the average latency, specifically for blocked requests. A user  102  gets an immediate block as opposed to a delay based on an exchange with the cloud service. Finally, this hybrid architecture approach increases the coverage of security policies/signature-based checks on mobile devices  300 , because the cloud based system  100  has significant processing capability relative to the mobile device  300 . Here, the application  350  is coordinating with the cloud service. The actual policies are configured in a cloud portal of the cloud-based system  100  and immediately promulgated to corresponding mobile devices  300 . The application  350  serves as a gatekeeper to process simple requests, namely BLOCK/ALLOW connections, based on entries in a local map. The cloud-based system  100  processes complex requests, where entries are not in the local map or where other security policies require, such as where data requires DLP analysis, etc. Again, mobile devices  300  have limited battery, storage, processing capabilities. The application  350  is lightweight and operates considering these limitations. The local map can be referred to as a cache of security policies. 
       FIG. 19  is a flowchart of a process  1100  for security processing in a hybrid architecture. The process  1100  is described with reference to steps at a mobile device  300 , and those skilled in the art will recognize functions are also performed in the cloud-based system  100 . The process  1100  contemplates implementation as a method, via the mobile device  300 , and as computer-executable instructions stored in a non-transitory computer-readable medium. 
     The process  1100  includes intercepting traffic on the mobile device  300  based on a set of rules (step  1102 ); determining whether a connection associated with the traffic is allowed based on a local map associated with an application  350  (step  1104 ); responsive to the connection being allowed or blocked based on the local map, one of forwarding the traffic associated with the connection when allowed and generating a block of the connection at the mobile device  300  when blocked (step  1106 ); and, responsive to the connection not having an entry in the local map, forwarding a request for the connection to a cloud-based system  100  for processing therein (step  1108 ). The cloud-based system  100  is configured to allow or block the connection based on the connection not having an entry in the local map. 
     There can be multiple different local maps, such as a firewall map, a domain map, and an HTTP request map. The firewall map can be the first map to consult for every connection. It has rules based on destination IP address, protocol, and port. The domain map, after the firewall map, can be consulted for HTTP and HTTPS connections. For HTTP, the application  350  can use the domain in the HTTP host header, and for HTTPS, the application  350  can use Server Name Indication (SNI). After the domain map, the HTTP domain map is consulted for HTTP requests, this map will have different set of rule categories such as: a) HTTP request type: Match HTTP domain (optional) and request type like GET/POST/HEAD, etc., b) HTTP header: Match HTTP request header key:value (optional) pairs and domain (optional), c) HTTP Version: Match Http version and domain (optional), d) Whole HTTP payload: Match http request payload SHA256 hash by excluding specific request headers. 
     The process  1100  can further include receiving an update from the cloud-based system  100  based on the forwarding the request to the cloud-based system  100 ; and updating the local map based on the update. Here, the application  350  is configured to cache previous decisions that were made by the cloud-based system  100 . The process  1100  can further include receiving periodic updates from the cloud-based system  100 ; and updating the local map based on the periodic updates. Here, the periodic updates can be based on new security policies for a tenant of the user, detections of connections as malware or other malicious content for blocking, etc. The periodic updates can be based on monitoring in the cloud-based system and on policy of a tenant associated with a user of the mobile device. 
     The process  1100  can also include timing out entries in the local map and removing timed out entries. Here, the local map can have entries purged over time. This is not an issue as the fallback for any connection not found in the local map is processing in the cloud-based system  100 . Thus, the local map does not need to have every possible connection entered in the local map; only ones that are used regularly. Each object within the map can have their own timeout determined based on the nature of block, e.g., for a firewall block, it can be more, and, for HTTP request payload block, it could be less. 
     In an embodiment, the traffic includes Hypertext Transfer Protocol (HTTP) and HTTP Secure (HTTPS) requests. The application  350  can intercept the HTTP/HTTPS requests on the mobile device  300  by means of route based rules. The routes added by the application  350  redirect all the traffic to itself via a virtual tun/tap adapter. For each incoming HTTP/HTTPS request, the application  350  consults the local map indicating if the connection needs to be blocked. In the case of BLOCK, it generates a local BLOCK response and sends it to the client application that generated the traffic. If the entry for this particular connection does not exist in the local map, the request is forwarded to the cloud service. Every BLOCK response from the cloud service can be saved locally in the local map for future consultation. There are several types of maps maintained on the client based on the type of BLOCK received from the cloud service. The process  1100  also contemplates non-HTTP/HTTPS traffic as well. 
     For a firewall map, if the request is forwarded to the cloud, a cloud firewall can provide the BLOCK and the decision can be provided to the local firewall map for future traffic. The updates between the application  350  and the cloud-based system  100  can be based on a tunnel. For example, a tunnel used between the mobile device  300 , the application  350 , and an enforcement node  150  can include information exchanged related to BLOCKs and the associated reasons. For example, DLP_VIOLATION, PROTOCOL_ACCESS_DENIED, etc. The local map can be populated based on the tunnel data. 
     Disaster Recovery 
     As described herein, the cloud-based system  100  is designed to have high availability through redundancy, the nodes  150  being in clusters, the nodes  150  being geographically distributed, etc. Also, as described herein, the cloud-based system  100  is configured to perform security processing functions. An example of the security processing functions can include allowing or blocking data traffic. Another example of the security processing functions can include the ZTNA where the cloud-based system  100  stitches the applications  402  and the software  400  together, on a per-user, per-application basis. In normal operation, the cloud-based system  100  is available to perform the security processing. Also, in normal operation, the cloud-based system  100  can work with the mobile device  300  in a hybrid architecture. 
     The present disclosure contemplates use of the local map described above with the application  350  with various user device  300  (not just mobile devices  300 ) in the context of disaster recovery. Disaster recovery means the cloud-based system  100  is not available for a user device  300  to provide security processing. The disaster can be unavailability of one or more of the nodes  150  in the cloud-based system  100 , unavailability of the entire cloud-based system  100 , network congestion, network failures, etc. That is, a disaster means the cloud-based system  100  is unavailable for any reason to perform security processing. 
       FIG. 20  is a flowchart of a process  1120  for disaster recovery via the hybrid architecture, i.e., cached policies on the user device  300 . The process  1120  contemplates implementation as a method, via the user device  300 , and as computer-executable instructions stored in a non-transitory computer-readable medium. The process  1120  includes intercepting traffic on the user device (step  1122 ); forwarding the traffic to a cloud-based system for security processing therein (step  1124 ); and, responsive to unavailability of the cloud-based system preventing the forwarding, performing local security processing of the traffic at the user device including determining whether the traffic is allowed based on a cache at the user device, forwarding the traffic separate from the cloud-based system when it is allowed, and blocking the traffic when it is not allowed (step  1126 ). 
     The user device  300  may or may not utilize the application  350 . The user device  300  is configured to intercept outbound traffic, such as described herein, to send to the cloud-based system  100  for security processing therein. The user device  300  can determine the cloud-based system  100  is unavailable for the forwarding, and then perform the local security processing. In an embodiment, the local security processing includes a local allow/block of traffic based on cached policies, e.g., in the local map. 
     The process  1120  can further include updating the cache based on the forwarding and actions taken by the cloud-based system (step  1128 ). That is, in an embodiment, the cache can be based on monitoring the user&#39;s activity, the decision by the cloud-based system  100 , e.g., block/allow, and storing the same in the cache. The process  1120  can further include obtaining a list for the cache that contains pre-configured domains (step  1130 ). Here, the cloud-based system  100  can provide a pre-configured list. For example, the list can be based on a tenant associated with the user device  300 . Also, the list can be based on a list of top domains, such as from Alexa or the like. Also, the cache can be a combination of a pre-configured list and learned behavior from operation. 
     In an embodiment, for the local security processing, the traffic is blocked based on a domain included in the cache. That is, the cache can include blocked domains as well as possible allowed domains. In another embodiment, for the local security processing, the traffic is blocked based on a domain not being in the cache. Here, the cache is an allowed list and any domain not in the cache is blocked. Of course, the local security processing can include any of these operational approaches. 
     The process  1120  can further include maintaining access logs locally at the user device for the local security processing; and forwarding the access logs to the cloud-based system after it is available. Here, there can be some amount of logging locally maintained while the cloud-based system  100  is unavailable to ensure visibility. The unavailability can be based on the cloud-based system being down beyond a threshold. The local security processing can be configured by a tenant. For example, a tenant may allow this local security processing as well as prevent it (here, unavailability of the cloud-based system  100  would mean no network access). 
     The local security processing can include other approaches besides allowing/blocking a domain. For example, the local security processing can include Zero Trust Network Access to an application included in an enterprise network, and the process  1120  can include providing a secure connection to the application  402  included in the enterprise network  404  based on the cache. Other local security processing techniques can include DLP and the like. 
     CONCLUSION 
     It will be appreciated that some embodiments described herein may include one or more generic or specialized processors (“one or more processors”) such as microprocessors; Central Processing Units (CPUs); Digital Signal Processors (DSPs): customized processors such as Network Processors (NPs) or Network Processing Units (NPUs), Graphics Processing Units (GPUs), or the like; Field Programmable Gate Arrays (FPGAs); and the like along with unique stored program instructions (including both software and firmware) for control thereof to implement, in conjunction with certain non-processor circuits, some, most, or all of the functions of the methods and/or systems described herein. Alternatively, some or all functions may be implemented by a state machine that has no stored program instructions, or in one or more Application-Specific Integrated Circuits (ASICs), in which each function or some combinations of certain of the functions are implemented as custom logic or circuitry. Of course, a combination of the aforementioned approaches may be used. For some of the embodiments described herein, a corresponding device such as hardware, software, firmware, and a combination thereof can be referred to as “circuitry configured or adapted to,” “logic configured or adapted to,” etc. perform a set of operations, steps, methods, processes, algorithms, functions, techniques, etc. as described herein for the various embodiments. 
     Moreover, some embodiments may include a non-transitory computer-readable storage medium having computer-readable code stored thereon for programming a computer, server, appliance, device, processor, circuit, etc. each of which may include a processor to perform functions as described and claimed herein. Examples of such computer-readable storage mediums include, but are not limited to, a hard disk, an optical storage device, a magnetic storage device, a ROM (Read Only Memory), a PROM (Programmable Read-Only Memory), an EPROM (Erasable Programmable Read-Only Memory), an EEPROM (Electrically Erasable Programmable Read-Only Memory), Flash memory, and the like. When stored in the non-transitory computer-readable medium, software can include instructions executable by a processor or device (e.g., any type of programmable circuitry or logic) that, in response to such execution, cause a processor or the device to perform a set of operations, steps, methods, processes, algorithms, functions, techniques, etc. as described herein for the various embodiments. 
     Although the present disclosure has been illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the art that other embodiments and examples may perform similar functions and/or achieve like results. All such equivalent embodiments and examples are within the spirit and scope of the present disclosure, are contemplated thereby, and are intended to be covered by the following claims.