Patent Publication Number: US-2023164116-A1

Title: Multi-tenant cloud-based firewall systems and methods

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present disclosure is a continuation of U.S. patent application Ser. No. 14/943,579, filed Nov. 17, 2015, and entitled “Multi-tenant cloud-based firewall systems and methods,” the contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE DISCLOSURE 
     The present disclosure generally relates to computer networking systems and methods. More particularly, the present disclosure relates to multi-tenant cloud-based firewall systems and methods. 
     BACKGROUND OF THE DISCLOSURE 
     In networks, firewalls monitor and control incoming and outgoing network traffic based on predetermined security rules. A firewall typically establishes a barrier between a trusted, secure internal network and another outside network, such as the Internet, that is assumed not to be secure or trusted. Firewalls are often categorized as either network firewalls or host-based firewalls. Network firewalls are a software appliance running on general-purpose hardware or hardware-based firewall computer appliances that filter traffic between two or more networks. Host-based firewalls provide a layer of software on one host that controls network traffic in and out of that single machine. Firewall appliances may also offer other functionality to the internal network they protect such as acting as a Dynamic Host Configuration Protocol (DHCP) or Virtual Private Network (VPN) server for that network. Disadvantageously, conventional firewalls, either network firewalls or host-based firewalls are physical devices located at the boundary between the internal network and the outside network (the Internet). That is, network firewalls are appliance-based at the network boundary, and host-based firewalls are on a single device. This scheme does not reflect the evolving network of cloud-based connectivity, Bring Your Own Device (BYOD), etc. For example, a road warrior, home user, or employee with their mobile device does not have the benefit of a network firewall outside of the internal network. Also, mobile devices and their associated operating systems may not allow host-based firewalls. 
     Thus, there is a need for next-generation firewall systems and methods that can adapt to the evolving network. 
     BRIEF SUMMARY OF THE DISCLOSURE 
     In an embodiment, a multi-tenant cloud-based firewall method from a client, performed by a cloud node, includes receiving a packet from the client, wherein the client is located externally from the cloud node; checking if a firewall session exists for the packet, and if so, processing the packet on a fast path where a lookup is performed to find the firewall session; if no firewall session exists, creating the firewall session; and processing the packet according to the firewall session and one or more rules. The cloud node can perform the method without a corresponding appliance or hardware on premises, at a location associated with the client, for providing a firewall. The client can be from one of a plurality of customers, each customer having its own rules for any of users, locations, departments, and groups. The cloud node can be part of a distributed security system and the method can further include processing the packet for a plurality of malware, spyware, viruses, email spam, Data Leakage Prevention, and content filtering. The client can be connected to the cloud node via one of Generic Routing Encapsulation (GRE) and an Internet Protocol (IP) security (IPsec) tunnel, regardless of location and device type of the client. The method can further include determining an application associated with the packet and subsequent packets in the firewall session utilizing Deep Packet Inspection (DPI). The DPI can include one or more of explicit classification, use of protocol data signatures, classification based on port, classification based on Internet Protocol (IP), pattern matching, and session correlation. The one or more rules operate over all ports and protocols. The one or more rules can include user-based rules based on identifying the client based on surrogation. 
     In another embodiment, a multi-tenant cloud-based firewall method from a server, performed by a cloud node, includes receiving a packet from the server, wherein the server is located externally from the cloud node; checking if a firewall session exists for the packet, and if so, processing the packet on a fast path where a lookup is performed to find the firewall session; if no firewall session exists, creating the firewall session; and processing the packet according to the firewall session and one or more rules. The cloud node performs the method without a corresponding appliance or hardware on premises, at a location associated with the server, for providing a firewall. The server communicates with a client from one of a plurality of customers, each customer having its own rules for any of users, locations, departments, and groups. The cloud node is part of a distributed security system, and the method further includes processing the packet for a plurality of malware, spyware, viruses, email spam, Data Leakage Prevention, and content filtering. The client can be connected to the cloud node via one of Generic Routing Encapsulation (GRE) and an Internet Protocol (IP) security (IPsec) tunnel, regardless of location and device type of the client. The method can further include determining an application associated with the packet and subsequent packets in the firewall session utilizing Deep Packet Inspection (DPI). The DPI can include one or more of explicit classification, use of protocol data signatures, classification based on port, classification based on Internet Protocol (IP), pattern matching, and session correlation. The one or more rules operate over all ports and protocols. The one or more rules can include user-based rules based on identifying the client based on surrogation. 
     In a further embodiment, a node in a cloud-based security system configured to provide a multi-tenant cloud-based firewall includes a network interface, a data store, and a processor communicatively coupled to one another; and memory storing computer executable instructions, and in response to execution by the processor, the computer-executable instructions cause the processor to perform steps of receive a packet from the a device, wherein the device is located externally from the cloud node; check if a firewall session exists for the packet, and if so, process the packet on a fast path where a lookup is performed to find the firewall session; if no firewall session exists, create the firewall session; and process the packet according to the firewall session and one or more rules. 
    
    
     
       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 distributed security system; 
         FIG.  2    is a network diagram of the distributed security system of  FIG.  1    illustrating various components in more detail; 
         FIG.  3    is a block diagram of a server which may be used in the distributed security system of  FIG.  1    or with any other cloud-based system; 
         FIG.  4    is a block diagram of a mobile device which may be used in the system of  FIG.  1    or with any other cloud-based system; 
         FIG.  5    is a network diagram of a generalized cloud-based system; 
         FIG.  6    is a network diagram of a network with a distributed security cloud providing DNS augmented security; 
         FIG.  7    is a network diagram of a network with a firewall in accordance with the multi-tenant cloud-based firewall systems and methods; 
         FIG.  8    is a network diagram of a network illustrating example use cases of the firewall; 
         FIG.  9    is a screenshot associated with the firewall illustrating example network services; 
         FIG.  10    is a screenshot associated with the firewall illustrates example applications; 
         FIG.  11    is a diagram of a Deep Packet Inspection (DPI) engine for the firewall; 
         FIG.  12 A  is a screenshot of defining a firewall filtering rule; 
         FIG.  12 B  is another screenshot of defining a firewall filtering rule; 
         FIG.  13    is screenshots of editing IP groups; 
         FIG.  14    is screenshots of editing a network service; 
         FIG.  15    is a flow diagram that illustrates packet flow through the cloud node; 
         FIG.  16    is a flowchart of a process for packet flow through the firewall from a client; 
         FIG.  17    is a flowchart of a process for packet flow through the firewall from a server; 
         FIG.  18    is a screenshot of creating firewall policies; 
         FIG.  19    is a screenshot of a NAT configuration; 
         FIG.  20    is a screenshot of a user authentication screen; 
         FIG.  21    is a screenshot of DNS policy; 
         FIG.  22    is a screenshot of a reporting screen for firewall insights; 
         FIG.  23    is a screenshot of an interactive report for firewall insights; 
         FIG.  24    is a screenshot of a graph of usage trends through the firewall; and 
         FIG.  25    is graphs of top firewall protocols in sessions and bytes. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     In various embodiments, multi-tenant cloud-based firewall systems and methods are described. The firewall systems and methods can operate overlaid with existing branch office firewalls or routers as well as eliminate the need for physical firewalls. The firewall systems and methods can protect users at user level control, regardless of location, device, etc., over all ports and protocols (not only ports 80/443) while providing administrators a single unified policy for Internet access and integrated reporting and visibility. In an embodiment, the firewall systems and methods can eliminate dedicated hardware at user locations (e.g., branch or regional offices, etc.), providing a software-based cloud solution, such as a Virtualized Network Function (VNF) in the cloud. The firewall systems and methods support application awareness to identify application regardless of port, protocol, evasive tactic, or Secure Sockets Layer (SSL); user awareness to identify users, groups, and locations regardless of physical Internet Protocol (IP) address; visibility and policy management providing globally unified administration, policy management, and reporting; threat protection and compliance to block threats and data leaks in real-time; high performance through an in-line cloud-based, scalable system; and cost effectiveness with rapid deployment. In an embodiment, the firewall systems and methods are described implemented through or in conjunction with a distributed, cloud-based security system and the firewall systems and methods can be integrated with sandboxing, web security, Data Leakage Prevention (DLP), content filtering, SSL inspection, malware protection, and cloud-scale correlation, anti-virus, bandwidth management reporting and analytics, and the like. 
     § 1.0 Example High-Level System Architecture—Cloud-based Security System 
     Referring to  FIG.  1   , in an embodiment, a block diagram illustrates a distributed security system  100 . The system  100  may, for example, be implemented as an overlay network in a wide area network (WAN), such as the Internet, a local area network (LAN), or the like. The system  100  includes processing nodes (PN)  110 , that proactively detect and preclude the distribution of security threats, e.g., malware, spyware, viruses, email spam, DLP, content filtering, etc., and other undesirable content sent from or requested by an external system. The processing nodes  110  can also log activity and enforce policies, including logging changes to the various components and settings in the system  100 . Example external systems may include an enterprise  200 , a computer device  220 , and a mobile device  230 , or other network and computing systems communicatively coupled to the system  100 . In an embodiment, each of the processing nodes  110  may include a decision system, e.g., data inspection engines that operate on a content item, e.g., a web page, a file, an email message, or some other data or data communication that is sent from or requested by one of the external systems. In an embodiment, all data destined for or received from the Internet is processed through one of the processing nodes  110 . In another embodiment, specific data specified by each external system, e.g., only email, only executable files, etc., is processed through one of the processing node  110 . 
     Each of the processing nodes  110  may generate a decision vector D=[d1, d2, . . . , dn] for a content item of one or more parts C=[c1, c2, . . . , 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 processing node  110  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 processing nodes  110  may be determined by the threat classification of the content item and on a security policy of the external system 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=[c1, c2, . . . , cm] of the content item, at any of the processing nodes  110 , any one of the data inspection engines generates an output that results in a classification of “violating.” 
     Each of the processing nodes  110  may be implemented by one or more of computer and communications devices, e.g., server computers, gateways, switches, etc., such as the server  300  described in  FIG.  3   . In an embodiment, the processing nodes  110  may serve as an access layer  150 . The access layer  150  may, for example, provide external system access to the security system  100 . In an embodiment, each of the processing nodes  110  may include Internet gateways and one or more servers, and the processing nodes  110  may be distributed through a geographic region, e.g., throughout a country, region, campus, etc. According to a service agreement between a provider of the system  100  and an owner of an external system, the system  100  may thus provide security protection to the external system at any location throughout the geographic region. 
     Data communications may be monitored by the system  100  in a variety of ways, depending on the size and data requirements of the external system. For example, an enterprise  200  may have multiple routers, switches, etc. that are used to communicate over the Internet, and the routers, switches, etc. may be configured to establish communications through the nearest (in traffic communication time, for example) processing node  110 . A mobile device  230  may be configured to communicate to a nearest processing node  110  through any available wireless access device, such as an access point, or a cellular gateway. A single computer device  220 , such as a consumer&#39;s personal computer, may have its browser and email program configured to access the nearest processing node  110 , which, in turn, serves as a proxy for the computer device  220 . Alternatively, an Internet provider may have all of its customer traffic processed through the processing nodes  110 . 
     In an embodiment, the processing nodes  110  may communicate with one or more authority nodes (AN)  120 . The authority nodes  120  may store policy data for each external system and may distribute the policy data to each of the processing nodes  110 . The policy may, for example, define security policies for a protected system, e.g., security policies for the enterprise  200 . Example policy data may define access privileges for users, websites and/or content that is disallowed, restricted domains, etc. The authority nodes  120  may distribute the policy data to the access nodes  110 . In an embodiment, the authority nodes  120  may also distribute threat data that includes the classifications of content items according to threat classifications, e.g., a list of known viruses, a list of known malware sites, spam email domains, a list of known phishing sites, etc. The distribution of threat data between the processing nodes  110  and the authority nodes  120  may be implemented by push and pull distribution schemes described in more detail below. In an embodiment, each of the authority nodes  120  may be implemented by one or more computer and communication devices, e.g., server computers, gateways, switches, etc., such as the server  300  described in  FIG.  3   . In some embodiments, the authority nodes  120  may serve as an application layer  170 . The application layer  170  may, for example, manage and provide policy data, threat data, and data inspection engines and dictionaries for the processing nodes  110 . 
     Other application layer functions may also be provided in the application layer  170 , such as a user interface (UI) front-end  130 . The user interface front-end  130  may provide a user interface through which users of the external systems may provide and define security policies, e.g., whether email traffic is to be monitored, whether certain web sites are to be precluded, etc. Another application capability that may be provided through the user interface front-end  130  is security analysis and log reporting. The underlying data on which the security analysis and log reporting functions operate are stored in logging nodes (LN)  140 , which serve as a data logging layer  170 . Each of the logging nodes  140  may store data related to security operations and network traffic processed by the processing nodes  110  for each external system. In an embodiment, the logging node  140  data may be anonymized so that data identifying an enterprise is removed or obfuscated. For example, identifying data may be removed to provide an overall system summary of security processing for all enterprises and users without revealing the identity of any one account. Alternatively, identifying data may be obfuscated, e.g., provide a random account number each time it is accessed, so that an overall system summary of security processing for all enterprises and users may be broken out by accounts without revealing the identity of any one account. In another embodiment, the identifying data and/or logging node  140  data may be further encrypted, e.g., so that only the enterprise (or user if a single user account) may have access to the logging node  140  data for its account. Other processes of anonymizing, obfuscating, or securing logging node  140  data may also be used. Note, as described herein, the systems and methods for tracking and auditing changes in a multi-tenant cloud system can be implemented in the data logging layer  160 , for example. 
     In an embodiment, an access agent  180  may be included in the external systems. For example, the access agent  180  is deployed in the enterprise  200 . The access agent  180  may, for example, facilitate security processing by providing a hash index of files on a client device to one of the processing nodes  110 , or may facilitate authentication functions with one of the processing nodes  110 , e.g., by assigning tokens for passwords and sending only the tokens to a processing node so that transmission of passwords beyond the network edge of the enterprise is minimized. Other functions and processes may also be facilitated by the access agent  180 . In an embodiment, the processing node  110  may act as a forward proxy that receives user requests to external servers addressed directly to the processing node  110 . In another embodiment, the processing node  110  may access user requests that are passed through the processing node  110  in a transparent mode. A protected system, e.g., enterprise  200 , may, for example, choose one or both of these modes. For example, a browser may be configured either manually or through the access agent  180  to access the processing node  110  in a forward proxy mode. In the forward proxy mode, all accesses are addressed to the processing node  110 . 
     In an embodiment, an enterprise gateway may be configured so that user requests are routed through the processing node  110  by establishing a communication tunnel between the enterprise gateway and the processing node  110 . For establishing the tunnel, existing protocols such as generic routing encapsulation (GRE), layer two tunneling protocol (L2TP), or other Internet Protocol (IP) security protocols may be used. In another embodiment, the processing nodes  110  may be deployed at Internet service provider (ISP) nodes. The ISP nodes may redirect subject traffic to the processing nodes  110  in a transparent proxy mode. Protected systems, such as the enterprise  200 , may use a multiprotocol label switching (MPLS) class of service for indicating the subject traffic that is to be redirected. For example, at or within the enterprise, the access agent  180  may be configured to perform MPLS labeling. In another transparent proxy mode embodiment, a protected system, such as the enterprise  200 , may identify the processing node  110  as a next hop router for communication with the external servers. 
     Generally, the distributed security system  100  may generally refer to an example cloud-based security system. Other cloud-based security systems and generalized cloud-based systems are contemplated for the systems and methods for tracking and auditing changes in a multi-tenant cloud system. 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, with no installed client version of an application required. Centralization gives cloud service providers complete control over the versions of the browser-based 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 distributed security system  100  is illustrated herein as one example embodiment of a cloud-based system, and those of ordinary skill in the art will recognize the tracking and auditing systems and methods contemplate operation on any cloud-based system. 
     § 2.0 Example Detailed System Architecture and Operation 
     Referring to  FIG.  2   , in an embodiment, a block diagram illustrates various components of the distributed security system  100  in more detail. Although  FIG.  2    illustrates only one representative component processing node  110 , authority node  120 , and logging node  140 , those of ordinary skill in the art will appreciate there may be many of each of the component nodes  110 ,  120 , and  140  present in the system  100 . A wide area network (WAN)  101 , such as the Internet, or some other combination of wired and/or wireless networks, communicatively couples the processing node  110 , the authority node  120 , and the logging node  140  to one another. The external systems  200 ,  220  and  230  likewise communicate over the WAN  101  with each other or other data providers and publishers. Some or all of the data communication of each of the external systems  200 ,  220  and  230  may be processed through the processing node  110 . 
       FIG.  2    also shows the enterprise  200  in more detail. The enterprise  200  may, for example, include a firewall (FW)  202  protecting an internal network that may include one or more enterprise servers  216 , a lightweight directory access protocol (LDAP) server  212 , and other data or data stores  214 . Another firewall  203  may protect an enterprise subnet that can include user computers  206  and  208  (e.g., laptop and desktop computers). The enterprise  200  may communicate with the WAN  101  through one or more network devices, such as a router, gateway, switch, etc. The LDAP server  212  may store, for example, user login credentials for registered users of the enterprise  200  system. Such credentials may include user identifiers, login passwords, and a login history associated with each user identifier. The other data stores  214  may include sensitive information, such as bank records, medical records, trade secret information, or any other information warranting protection by one or more security measures. 
     In an embodiment, a client access agent  180   a  may be included on a client computer  208 . The client access agent  180   a  may, for example, facilitate security processing by providing a hash index of files on the user computer  208  to a processing node  110  for malware, virus detection, etc. Other security operations may also be facilitated by the access agent  180   a . In another embodiment, a server access agent  180  may facilitate authentication functions with the processing node  110 , e.g., by assigning tokens for passwords and sending only the tokens to the processing node  110  so that transmission of passwords beyond the network edge of the enterprise  200  is minimized. Other functions and processes may also be facilitated by the server access agent  180   b . The computer device  220  and the mobile device  230  may also store information warranting security measures, such as personal bank records, medical information, and login information, e.g., login information to the server  206  of the enterprise  200 , or to some other secured data provider server. The computer device  220  and the mobile device  230  can also store information warranting security measures, such as personal bank records, medical information, and login information, e.g., login information to a server  216  of the enterprise  200 , or to some other secured data provider server. 
     § 2.1 Example Processing Node Architecture 
     In an embodiment, the processing nodes  110  are external to network edges of the external systems  200 ,  220 , and  230 . Each of the processing nodes  110  stores security policies  113  received from the authority node  120  and monitors content items requested by or sent from the external systems  200 ,  220 , and  230 . In an embodiment, each of the processing nodes  110  may also store a detection process filter  112  and/or threat data  114  to facilitate the decision of whether a content item should be processed for threat detection. A processing node manager  118  may manage each content item in accordance with the security policy data  113 , and the detection process filter  112  and/or threat data  114 , if stored at the processing node  110 , so that security policies for a plurality of external systems in data communication with the processing node  110  are implemented external to the network edges for each of the external systems  200 ,  220  and  230 . For example, depending on the classification resulting from the monitoring, the content item may be allowed, precluded, or threat detected. In general, content items that are already classified as “clean” or not posing a threat can be allowed, while those classified as “violating” may be precluded. Those content items having an unknown status, e.g., content items that have not been processed by the system  100 , may be threat detected to classify the content item according to threat classifications. 
     The processing node  110  may include a state manager  116 A. The state manager  116 A may be used to maintain the authentication and the authorization states of users that submit requests to the processing node  110 . Maintenance of the states through the state manager  116 A may minimize the number of authentication and authorization transactions that are necessary to process a request. The processing node  110  may also include an epoch processor  116 B. The epoch processor  116 B may be used to analyze authentication data that originated at the authority node  120 . The epoch processor  116 B may use an epoch ID to validate further the authenticity of authentication data. The processing node  110  may further include a source processor  116 C. The source processor  116 C may be used to verify the source of authorization and authentication data. The source processor  116 C may identify improperly obtained authorization and authentication data, enhancing the security of the network. Collectively, the state manager  116 A, the epoch processor  116 B, and the source processor  116 C operate as data inspection engines. 
     Because the amount of data being processed by the processing nodes  110  may be substantial, the detection processing filter  112  may be used as the first stage of an information lookup procedure. For example, the detection processing filter  112  may be used as a front end to a looking of the threat data  114 . Content items may be mapped to index values of the detection processing filter  112  by a hash function that operates on an information key derived from the information item. The information key is hashed to generate an index value (i.e., a bit position). A value of zero in a bit position in the guard table can indicate, for example, the absence of information, while a one in that bit position can indicate the presence of information. Alternatively, a one could be used to represent absence, and a zero to represent presence. Each content item may have an information key that is hashed. For example, the processing node manager  118  may identify the Uniform Resource Locator (URL) address of URL requests as the information key and hash the URL address; or may identify the file name and the file size of an executable file information key and hash the file name and file size of the executable file. Hashing an information key to generate an index and checking a bit value at the index in the detection processing filter  112  generally requires less processing time than actually searching threat data  114 . The use of the detection processing filter  112  may improve the failure query (i.e., responding to a request for absent information) performance of database queries and/or any general information queries. Because data structures are generally optimized to access information that is present in the structures, failure query performance has a greater effect on the time required to process information searches for very rarely occurring items, e.g., the presence of file information in a virus scan log or a cache where many or most of the files transferred in a network have not been scanned or cached. Using the detection processing filter  112 , however, the worst-case additional cost is only on the order of one, and thus its use for most failure queries saves on the order of m log m, where m is the number of information records present in the threat data  114 . 
     The detection processing filter  112  thus improves the performance of queries where the answer to a request for information is usually positive. Such instances may include, for example, whether a given file has been virus scanned, whether content at a given URL has been scanned for inappropriate (e.g., pornographic) content, whether a given fingerprint matches any of a set of stored documents, and whether a checksum corresponds to any of a set of stored documents. Thus, if the detection processing filter  112  indicates that the content item has not been processed, then a worst-case null lookup operation into the threat data  114  is avoided, and threat detection can be implemented immediately. The detection processing filter  112  thus complements the threat data  114  that capture positive information. In an embodiment, the detection processing filter  112  may be a Bloom filter implemented by a single hash function. The Bloom filter may be sparse table, i.e., the tables include many zeros and few ones, and the hash function is chosen to minimize or eliminate false negatives which are, for example, instances where an information key is hashed to a bit position, and that bit position indicates that the requested information is absent when it is actually present. 
     § 2.2 Example Authority Node Architecture 
     In general, the authority node  120  includes a data store that stores master security policy data  123  for each of the external systems  200 ,  220 , and  230 . An authority node manager  128  may be used to manage the master security policy data  123 , e.g., receive input from users of each of the external systems defining different security policies, and may distribute the master security policy data  123  to each of the processing nodes  110 . The processing nodes  110  then store a local copy of the security policy data  113 . The authority node  120  may also store a master detection process filter  122 . The detection processing filter  122  may include data indicating whether content items have been processed by one or more of the data inspection engines  116  in any of the processing nodes  110 . The authority node manager  128  may be used to manage the master detection processing filter  122 , e.g., receive updates from processing nodes  110  when the processing node  110  has processed a content item and update the master detection processing filter  122 . For example, the master detection processing filter  122  may be distributed to the processing nodes  110 , which then stores a local copy of the detection processing filter  112 . 
     In an embodiment, the authority node  120  may include an epoch manager  126 . The epoch manager  126  may be used to generate authentication data associated with an epoch ID. The epoch ID of the authentication data is a verifiable attribute of the authentication data that can be used to identify fraudulently created authentication data. In an embodiment, the detection processing filter  122  may be a guard table. The processing node  110  may, for example, use the information in the local detection processing filter  112  to quickly determine the presence and/or absence of information, e.g., whether a particular URL has been checked for malware; whether a particular executable has been virus scanned, etc. The authority node  120  may also store master threat data  124 . The master threat data  124  may classify content items by threat classifications, e.g., a list of known viruses, a list of known malware sites, spam email domains, a list of known or detected phishing sites, etc. The authority node manager  128  may be used to manage the master threat data  124 , e.g., receive updates from the processing nodes  110  when one of the processing nodes  110  has processed a content item and update the master threat data  124  with any pertinent results. In some implementations, the master threat data  124  may be distributed to the processing nodes  110 , which then store a local copy of the threat data  114 . In another embodiment, the authority node  120  may also monitor the health of each of the processing nodes  110 , e.g., the resource availability in each of the processing nodes  110 , detection of link failures, etc. Based on the observed health of each of the processing nodes  110 , the authority node  120  may redirect traffic among the processing nodes  110  and/or balance traffic among the processing nodes  110 . Other remedial actions and processes may also be facilitated by the authority node  110 . 
     § 2.3 Example Processing Node and Authority Node Communications 
     The processing node  110  and the authority node  120  may be configured according to one or more push and pull processes to manage content items according to security policy data  113  and/or  123 , detection process filters  112  and/or  122 , and the threat data  114  and/or  124 . In a threat data push implementation, each of the processing nodes  110  stores policy data  113  and threat data  114 . The processing node manager  118  determines whether a content item requested by or transmitted from an external system is classified by the threat data  114 . If the content item is determined to be classified by the threat data  114 , then the processing node manager  118  may manage the content item according to the security classification of the content item and the security policy of the external system. If, however, the content item is determined not to be classified by the threat data  114 , then the processing node manager  118  may cause one or more of the data inspection engines  117  to perform the threat detection processes to classify the content item according to a threat classification. Once the content item is classified, the processing node manager  118  generates a threat data update that includes data indicating the threat classification for the content item from the threat detection process and transmits the threat data update to an authority node  120 . 
     The authority node manager  128 , in response to receiving the threat data update, updates the master threat data  124  stored in the authority node data store according to the threat data update received from the processing node  110 . In an embodiment, the authority node manager  128  may automatically transmit the updated threat data to the other processing nodes  110 . Accordingly, threat data for new threats as the new threats are encountered are automatically distributed to each processing node  110 . Upon receiving the new threat data from the authority node  120 , each of processing node managers  118  may store the updated threat data in the locally stored threat data  114 . 
     In a threat data pull and push implementation, each of the processing nodes  110  stores policy data  113  and threat data  114 . The processing node manager  118  determines whether a content item requested by or transmitted from an external system is classified by the threat data  114 . If the content item is determined to be classified by the threat data  114 , then the processing node manager  118  may manage the content item according to the security classification of the content item and the security policy of the external system. If, however, the content item is determined not to be classified by the threat data, then the processing node manager  118  may request responsive threat data for the content item from the authority node  120 . Because processing a content item may consume valuable resource and time, in some implementations, the processing node  110  may first check with the authority node  120  for threat data  114  before committing such processing resources. 
     The authority node manager  128  may receive the responsive threat data request from the processing node  110  and may determine if the responsive threat data is stored in the authority node data store. If responsive threat data is stored in the master threat data  124 , then the authority node manager  128  provide a reply that includes the responsive threat data to the processing node  110  so that the processing node manager  118  may manage the content item in accordance with the security policy data  112  and the classification of the content item. Conversely, if the authority node manager  128  determines that responsive threat data is not stored in the master threat data  124 , then the authority node manager  128  may provide a reply that does not include the responsive threat data to the processing node  110 . In response, the processing node manager  118  can cause one or more of the data inspection engines  116  to perform the threat detection processes to classify the content item according to a threat classification. Once the content item is classified, the processing node manager  118  generates a threat data update that includes data indicating the threat classification for the content item from the threat detection process, and transmits the threat data update to an authority node  120 . The authority node manager  128  can then update the master threat data  124 . Thereafter, any future requests related to responsive threat data for the content item from other processing nodes  110  can be readily served with responsive threat data. 
     In a detection process filter and threat data push implementation, each of the processing nodes  110  stores a detection process filter  112 , policy data  113 , and threat data  114 . The processing node manager  118  accesses the detection process filter  112  to determine whether the content item has been processed. If the processing node manager  118  determines that the content item has been processed, it may determine if the content item is classified by the threat data  114 . Because the detection process filter  112  has the potential for a false positive, a lookup in the threat data  114  may be implemented to ensure that a false positive has not occurred. The initial check of the detection process filter  112 , however, may eliminate many null queries to the threat data  114 , which, in turn, conserves system resources and increases efficiency. If the content item is classified by the threat data  114 , then the processing node manager  118  may manage the content item in accordance with the security policy data  113  and the classification of the content item. Conversely, if the processing node manager  118  determines that the content item is not classified by the threat data  114 , or if the processing node manager  118  initially determines through the detection process filter  112  that the content item is not classified by the threat data  114 , then the processing node manager  118  may cause one or more of the data inspection engines  116  to perform the threat detection processes to classify the content item according to a threat classification. Once the content item is classified, the processing node manager  118  generates a threat data update that includes data indicating the threat classification for the content item from the threat detection process, and transmits the threat data update to one of the authority nodes  120 . 
     The authority node manager  128 , in turn, may update the master threat data  124  and the master detection process filter  122  stored in the authority node data store according to the threat data update received from the processing node  110 . In an embodiment, the authority node manager  128  may automatically transmit the updated threat data and detection processing filter to other processing nodes  110 . Accordingly, threat data and the detection processing filter for new threats, as the new threats are encountered, are automatically distributed to each processing node  110 , and each processing node  110  may update its local copy of the detection processing filter  112  and threat data  114 . 
     In a detection process filter and threat data pull and push implementation, each of the processing nodes  110  stores a detection process filter  112 , policy data  113 , and threat data  114 . The processing node manager  118  accesses the detection process filter  112  to determine whether the content item has been processed. If the processing node manager  118  determines that the content item has been processed, it may determine if the content item is classified by the threat data  114 . Because the detection process filter  112  has the potential for a false positive, a lookup in the threat data  114  can be implemented to ensure that a false positive has not occurred. The initial check of the detection process filter  112 , however, may eliminate many null queries to the threat data  114 , which, in turn, conserves system resources and increases efficiency. If the processing node manager  118  determines that the content item has not been processed, it may request responsive threat data for the content item from the authority node  120 . Because processing a content item may consume valuable resource and time, in some implementations, the processing node  110  may first check with the authority node  120  for threat data  114  before committing such processing resources. 
     The authority node manager  128  may receive the responsive threat data request from the processing node  110  and may determine if the responsive threat data is stored in the authority node data  120  store. If responsive threat data is stored in the master threat data  124 , then the authority node manager  128  provides a reply that includes the responsive threat data to the processing node  110  so that the processing node manager  118  can manage the content item in accordance with the security policy data  112  and the classification of the content item, and further update the local detection processing filter  112 . Conversely, if the authority node manager  128  determines that responsive threat data is not stored in the master threat data  124 , then the authority node manager  128  may provide a reply that does not include the responsive threat data to the processing node  110 . In response, the processing node manager  118  may cause one or more of the data inspection engines  116  to perform the threat detection processes to classify the content item according to a threat classification. Once the content item is classified, the processing node manager  118  generates a threat data update that includes data indicating the threat classification for the content item from the threat detection process, and transmits the threat data update to an authority node  120 . The authority node manager  128  may then update the master threat data  124 . Thereafter, any future requests for related to responsive threat data for the content item from other processing nodes  110  can be readily served with responsive threat data. 
     The various push and pull data exchange processes provided above are example processes for which the threat data and/or detection process filters may be updated in the system  100  of  FIGS.  1  and  2   . Other update processes, however, are contemplated with the present invention. The data inspection engines  116 , processing node manager  118 , authority node manager  128 , user interface manager  132 , logging node manager  148 , and authority agent  180  may be realized by instructions that upon execution cause one or more processing devices to carry out the processes and functions described above. Such instructions can, for example, include interpreted instructions, such as script instructions, e.g., JavaScript or ECMAScript instructions, or executable code, or other instructions stored in a non-transitory computer-readable medium. Other processing architectures can also be used, e.g., a combination of specially designed hardware and software, for example. 
     § 3.0 Example Server Architecture 
     Referring to  FIG.  3   , in an embodiment, a block diagram illustrates a server  300  which may be used in the system  100 , in other systems, or standalone. Any of the processing nodes  110 , the authority nodes  120 , and the logging nodes  140  may be formed through one or more servers  300 . Further, the computer device  220 , the mobile device  230 , the servers  208 ,  216 , etc. may include the server  300  or a similar structure. The server  300  may be a digital computer that, in terms of hardware architecture, generally includes a processor  302 , input/output (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.  3    depicts the server  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  310 ) are communicatively coupled via a local interface  312 . The local interface  312  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  312  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  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  may be any custom made or commercially available processor, a central processing unit (CPU), an auxiliary processor among several processors associated with the server  300 , a semiconductor-based microprocessor (in the form of a microchip or chipset), or generally any device for executing software instructions. When the server  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 server  300  pursuant to the software instructions. The I/O interfaces  304  may be used to receive user input from and/or for providing system output to one or more devices or components. The user input may be provided via, for example, a keyboard, touchpad, and/or a mouse. System output may be provided via a display device and a printer (not shown). I/O interfaces  304  may include, for example, a serial port, a parallel port, a small computer system interface (SCSI), a serial ATA (SATA), a fibre channel, Infiniband, iSCSI, a PCI Express interface (PCI-x), an infrared (IR) interface, a radio frequency (RF) interface, and/or a universal serial bus (USB) interface. 
     The network interface  306  may be used to enable the server  300  to communicate over a network, such as the Internet, the WAN  101 , the enterprise  200 , and the like, etc. The network interface  306  may include, for example, an Ethernet card or adapter (e.g., 10BaseT, Fast Ethernet, Gigabit Ethernet,  10 GbE) or a wireless local area network (WLAN) card or adapter (e.g., 802.11a/b/g/n). The network interface  306  may include address, control, and/or data connections to enable appropriate communications on the network. A 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. In one example, the data store  1208  may be located internal to the server  300 , such as, for example, an internal hard drive connected to the local interface  312  in the server  300 . Additionally, in another embodiment, the data store  308  may be located external to the server  300  such as, for example, an external hard drive connected to the I/O interfaces  304  (e.g., SCSI or USB connection). In a further embodiment, the data store  308  may be connected to the server  300  through a network, such as, for example, a network-attached file server. 
     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, tape, CDROM, 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  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  310  includes a suitable operating system (O/S)  314  and one or more programs  316 . The operating system  314  essentially controls the execution of other computer programs, such as the one or more programs  316 , and provides scheduling, input-output control, file and data management, memory management, and communication control and related services. The one or more programs  316  may be configured to implement the various processes, algorithms, methods, techniques, etc. described herein. 
     § 4.0 Example Mobile Device Architecture 
     Referring to  FIG.  4   , in an embodiment, a block diagram illustrates a mobile device  400 , which may be used in the system  100  or the like. The mobile device  400  can be a digital device that, in terms of hardware architecture, generally includes a processor  402 , input/output (I/O) interfaces  404 , a radio  406 , a data store  408 , and memory  410 . It should be appreciated by those of ordinary skill in the art that  FIG.  4    depicts the mobile device  410  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 ( 402 ,  404 ,  406 ,  408 , and  402 ) are communicatively coupled via a local interface  412 . The local interface  412  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  412  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  412  may include address, control, and/or data connections to enable appropriate communications among the aforementioned components. 
     The processor  402  is a hardware device for executing software instructions. The processor  402  can be any custom made or commercially available processor, a central processing unit (CPU), an auxiliary processor among several processors associated with the mobile device  410 , a semiconductor-based microprocessor (in the form of a microchip or chipset), or generally any device for executing software instructions. When the mobile device  410  is in operation, the processor  402  is configured to execute software stored within the memory  410 , to communicate data to and from the memory  410 , and to generally control operations of the mobile device  410  pursuant to the software instructions. In an embodiment, the processor  402  may include an optimized mobile processor such as optimized for power consumption and mobile applications. The I/O interfaces  404  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, 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 I/O interfaces  404  can also include, for example, a serial port, a parallel port, a small computer system interface (SCSI), an infrared (IR) interface, a radio frequency (RF) interface, a universal serial bus (USB) interface, and the like. The I/O interfaces  404  can include a graphical user interface (GUI) that enables a user to interact with the mobile device  410 . Additionally, the I/O interfaces  404  may further include an imaging device, i.e., camera, video camera, etc. 
     The radio  406  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 radio  406 , including, without limitation: RF; IrDA (infrared); Bluetooth; ZigBee (and other variants of the IEEE 802.15 protocol); IEEE 802.11 (any variation); IEEE 802.16 (WiMAX or any other variation); Direct Sequence Spread Spectrum; Frequency Hopping Spread Spectrum; Long Term Evolution (LTE); cellular/wireless/cordless telecommunication protocols (e.g., 3G/4G, etc.); wireless home network communication protocols; paging network protocols; magnetic induction; satellite data communication protocols; wireless hospital or health care facility network protocols such as those operating in the WMTS bands; GPRS; proprietary wireless data communication protocols such as variants of Wireless USB; and any other protocols for wireless communication. The data store  408  may be used to store data. The data store  408  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  408  may incorporate electronic, magnetic, optical, and/or other types of storage media. 
     The memory  410  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  410  may incorporate electronic, magnetic, optical, and/or other types of storage media. Note that the memory  410  may have a distributed architecture, where various components are situated remotely from one another, but can be accessed by the processor  402 . The software in memory  410  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.  4   , the software in the memory  410  includes a suitable operating system (O/S)  414  and programs  416 . The operating system  414  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  416  may include various applications, add-ons, etc. configured to provide end-user functionality with the mobile device  400 . For example, example programs  416  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  416  along with a network such as the system  100 . 
     § 5.0 Example General Cloud System 
     Referring to  FIG.  5   , in an embodiment, a cloud system  500  is illustrated for implementing the systems and methods described herein for tracking and auditing changes in a multi-tenant cloud system. The cloud system  500  includes one or more cloud nodes (CN)  502  communicatively coupled to the Internet  504 . The cloud nodes  502  may include the processing nodes  110 , the server  300 , or the like. That is, the cloud system  500  may include the distributed security system  100  or another implementation of a cloud0based system, such as a system providing different functionality from security. In the cloud system  500 , traffic from various locations (and various devices located therein) such as a regional office  510 , headquarters  520 , various employee&#39;s homes  530 , mobile laptop  540 , and mobile device  542  communicates to the cloud through the cloud nodes  502 . That is, each of the locations  510 ,  520 ,  530 ,  540 ,  542  is communicatively coupled to the Internet  504  through the cloud nodes  502 . For security, the cloud system  500  may be configured to perform various functions such as spam filtering, uniform resource locator (URL) filtering, antivirus protection, bandwidth control, data loss prevention, zero-day vulnerability protection, web  2 . 0  features, and the like. In an embodiment, the cloud system  500  and the distributed security system  100  may be viewed as Security-as-a-Service through the cloud. In general, the cloud system  500  can be configured to perform any function in a multi-tenant environment. For example, the cloud system  500  can provide content, a collaboration between users, storage, application hosting, and the like. 
     In an embodiment, the cloud system  500  can utilize the systems and methods for tracking and auditing changes in a multi-tenant cloud system. That is, the cloud system  500  can track and audit administrator activity associated with the cloud system  500  in a segregated and overlaid fashion from the application functions performed by the cloud system  500 . This segregated and overlaid fashion decouples the tracking and auditing from application logic, maximizing resources, and minimizing development complexity and runtime processing. The cloud system  500  (and the system  100 ) can be offloaded from complex tracking and auditing functions so that it can provide its primary function. In the context of a distributed security system, the tracking and auditing systems and methods enable accountability, intrusion detection, problem diagnosis, and data reconstruction, all in an optimized fashion considering the exponential growth in cloud-based systems. 
     § 6.0 DNS Augmented Security 
     In an embodiment, the cloud system  500  and/or the distributed security system  100  can be used to perform DNS surrogation. Specifically, DNS surrogation can be a framework for distributed or cloud-based security/monitoring, as is described herein. Endpoint security is no longer effective as deployments move to the cloud with users accessing content from a plurality of devices in an anytime, anywhere connected manner. As such, cloud-based security is the most effective means to ensure network protection where different devices are used to access network resources. Traffic inspection in the distributed security system  100  and the cloud-based system  500  is performed in an in-line manner, i.e., the processing nodes  110  and the cloud nodes  500  are in the data path of connecting users. Another approach can include a passive approach to the data path. DNS is one of the most fundamental IP protocols. With DNS surrogation as a technique, it is proposed to use DNS for dynamic routing of traffic, per-user authentication and policy enforcement, and the like. 
     In conjunction with the cloud system  500  and/or the distributed security system  100 , various techniques can be used for monitoring which are described on a sliding scale between always inline to never inline. First, in an always inline manner, all user traffic is between inline proxies such as the processing nodes  110  or the cloud nodes  502  without exception. Here, DNS can be used as a forwarding mechanism to the inline proxies. Second, in a somewhat always inline manner, all user traffic except for certain business partners or third parties is between inline proxies such as the processing nodes  110  or the cloud nodes  502 . Third, in an inline manner for most traffic, high bandwidth applications can be configured to bypass the inline proxies such as the processing nodes  110  or the cloud nodes  502 . Example high bandwidth applications can include content streaming such as video (e.g., Netflix, Hulu, YouTube, etc.) or audio (e.g., Pandora, etc.). Fourth, in a mixed manner, inline monitoring can be used for “interesting” traffic as determined by security policy with other traffic being direct. Fifth, in an almost never inline manner, simple domain-level URL filtering can be used to determine what is monitored inline. Finally, sixth, in a never inline manner, DNS augmented security can be used. 
     Referring to  FIG.  6   , in an embodiment, a network diagram illustrates a network  550  with a distributed security cloud  552  providing DNS augmented security. The network  550  includes a user device  554  connecting to the distributed security cloud  552  via an anycast DNS server  556 . The anycast DNS server  556  can be a server such as the server  300  of  FIG.  3   . Also, the anycast DNS server  556  can be the processing node  110 , the cloud node  502 , etc. The distributed security cloud  552  includes the anycast DNS server  556 , policy data  558 , and an inline proxy  560 . The inline proxy  560  can include the processing node  110 , the cloud node  502 , etc. In operation, the user device  554  is configured with a DNS entry of the anycast DNS server  556 , and the anycast DNS server  556  can perform DNS surrogation as is described herein. The distributed security cloud  552  utilizes the anycast DNS server  556 , the policy data  558 , and the inline proxy  560  to perform the DNS augmented security. 
     The network  550  illustrates the DNS augmented security where DNS information is used as follows. First, at step  562 , the user device  554  requests a DNS lookup of a site, e.g., “what is the IP address of site.com?” from the anycast DNS server  556 . The anycast DNS server  556  accesses the policy data  558  to determine the policy associated with the site at step  564 . The anycast DNS server  556  returns the IP address of the site based on the appropriate policy at step  566 . The policy data  558  determines if the site either goes direct (step  568 ) to the Internet, is inspected by the inline proxy (step  570 ), or is blocked per policy (step  572 ). Here, the anycast DNS server  556  returns the IP address with additional information if the site is inspected or blocked. For example, if the anycast DNS server  556  determines the access is direct, the anycast DNS server  556  simply returns the IP address of the site. If the anycast DNS server  556  determines the site is blocked or inspected, the anycast DNS server  556  returns the IP address to the inline proxy  560  with additional information. The inline proxy  560  can block the site or provide fully inline proxied traffic to the site (step  574 ) after performing monitoring for security. 
     The DNS augmented security advantageously is protocol and application-agnostic, providing visibility and control across virtually all Internet-bound traffic. For example, DNS-based protocols include Internet Relay Chat (IRC), Session Initiation Protocol (SIP), Hypertext Transfer Protocol (HTTP), HTTP Secure (HTTPS), Post Office Protocol v3 (POP3), Internet Message Access Protocol (IMAP), etc. Further, emerging threats are utilizing DNS today especially Botnets and advanced persistent threats (APTs). For example, Fast flux is a DNS technique used to hide phishing and malware delivery sites behind an ever-changing network of compromised hosts acting as proxies. The DNS augmented security provides deployment flexibility when full inline monitoring is not feasible. For example, this can be utilized in highly distributed with high bandwidth environments, in locations with challenging Internet Access, etc. The DNS augmented security can provide URL filtering, white/blacklist enforcement, etc. for enhanced security without content filtering. In this manner, the network  550  can be used with the distributed security system  100  and the cloud system  500  to provide cloud-based security without requiring full inline connectivity. 
     § 7.0 Multi-tenant, Cloud-based Firewall 
     Referring to  FIG.  7   , in an embodiment, a network diagram illustrates a network  600  with a firewall  602  in accordance with the multi-tenant cloud-based firewall systems and methods. The firewall  602  is functionally deployed through the cloud system  500  where traffic from various locations (and various devices located therein) such as a regional office/Branch office  510 , headquarters  520 , various employee&#39;s homes  530 , mobile laptop  540 , and mobile device  542  communicates to the Internet  504  through the cloud nodes  502 . The firewall  602  can be implemented through the cloud node  502  to allow or block data between the users and the Internet  504 . The firewall  602  could also be implemented through the processing node  110 . Note, in the various descriptions that follow, reference is made to the cloud node  502 , but those of ordinary skill in the art will recognize the processing node  110  can be used as well or any other type of server or node. Further, the firewall  602  can be communicatively coupled to a log  604  for logging associated data therein. In an embodiment, the cloud nodes  502  can be used only to provide the firewall  602 . In another embodiment, the cloud nodes  502  can provide the firewall  602  as well as in-line inspection. The firewall  602  can handle various types of data, such as, for example, Session Initiation Protocol (SIP), Internet Message Access Protocol (IMAP), Internet Relay Chat (IRC), Simple Mail Transfer Protocol (SMTP), Secure Shell (SSH), and the like. 
     Users connect to the cloud system  500  via Internet Protocol Security (IPsec) or GRE, all traffic, including non-HTTP traffic may be sent through the cloud nodes  502 . The firewall systems and methods propose to add support for non-HTTP applications to the cloud nodes  502 . Thus, the cloud system  500  is able to support non-Web traffic and act as a Firewall for the Branch office, where clients typically sit behind a hardware-based firewall to connect to servers outside the hardware-based firewall. The firewall  602  provides advanced security functionality in the cloud that can be used to offload Branch office Customer Premises Equipment (CPE). 
     Advantageously, in the cloud system  500 , processor and resource-intensive features are scalable, efficiently used for multiple customers, and inexpensive, relative to on-premises hardware-based solutions. The firewall  602  can be used to replace traditional expensive appliance box solutions that reside at the customer premise with service from the cloud system  500 . This enables end customers to realize cost savings, provide efficient growth, and unified management/reporting. For example, the cloud system  500  scales while appliance box solutions do not. On-premises hardware-based solutions are often integrated with feature-rich routers or operate as a stand-alone device. In both scenarios, the firewall  602  can provide cost savings, either removing the need for the stand-alone device or allowing the use of lower-cost routers and/or lower cost firewalls. The firewall  602 , through the cloud system  500 , can offer granular Layer 3 (L3) through Layer 7 (L7) control of applications, in a multi-tenant cloud infrastructure. This also includes integrated logging functionality, giving customers visibility into applications down to the L3 applications running on their networks. 
     § 7.1 Multi-tenant, Cloud-based Firewall—Use Cases 
     Referring to  FIG.  8   , in an embodiment, a network diagram illustrates a network  600 A illustrating example use cases of the firewall  602 . Here, the firewall  602  can support multiple customers, such as regional office/Branch offices  510 A,  510 B. That is, the cloud system  500  can support the firewall  602  for more than one customer at a time. Additionally, the firewall  602  can support a road warrior, i.e., the user device  554 , outside the office. 
     In an embodiment, the firewall  602  can be an outbound firewall for a Branch office, such as for large distributed enterprises, medium-size business, small business, and the like, with users sitting behind the firewall  602  and connecting to the cloud nodes  502  which allow outbound connections of various protocols. Traffic can come to the firewall  602  via IPSEC or GRE tunnels. Traffic can also come to the firewall  602  in a Layer 2 (L2) Transparent Mode where Virtual Local Area Network (VLAN) tags are used, such as a specific tag mapped to a particular customer. In another embodiment, the firewall  602  can be an outbound firewall for Branch offices for Managed Service Provided, replacing existing managed firewall servers where large amounts of appliances are installed in data centers. 
     The firewall  602  also can provide basic stateful firewall functionality for common Layer 3 (L3) applications, allowing for the configuration of any one of these applications to traverse through the firewall  602 . The user will now be capable of managing and controlling which protocols and applications are allowed through the firewall  602  and which ones are dropped. 
     For example, Telnet traffic can be configured to be allowed, and all other non-HTTP/HTTPS traffic to be dropped. Inbound functionality or any connections initiated by users coming from the Internet  504  can also be supported. The firewall  602  also includes an ability to support configuration policy rules and the ability to log all traffic and generate reports for the customer. 
     In an embodiment, the regional office/Branch offices  510 A,  510 B can each connect to the cloud system via an IPSec tunnel, configured for all traffic, including non-HTTP/HTTPS. This traffic can be Network Address Translation (NAT) out to the Internet  504 , and return traffic is passed back through the appropriate tunnel. Because the cloud system  500  knows which customer and which location traffic originated, the return traffic can be mapped properly and sent back through the appropriate VPN tunnel, even though customers may have overlapping private address spaces. 
     § 7.2 Multi-tenant, Cloud-based Firewall—Functionality 
     A firewall service is defined to be a traditional Layer 4 (L4) service that can be defined by ports and Ethernet protocol (Telnet, SSH, POP, IMAP, etc.). Firewall applications are defined as Layer 7 (L7) applications (e.g., Lync, Skype, YouTube, etc.). The firewall  602  enables custom firewall services to allow users to define their own pinholes through the FW firewall  602  if a pre-defined firewall application does not exist. This will be known as a custom-defined application that requires support for the custom application name and the configuration of ports or port ranges. This custom-defined application can override any pre-defined applications, and the custom-defined application cannot be defined with conflicting port ranges. 
     The firewall  602  can support pre-defined applications including, but not limited to, the following: 
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 HTTP 
                 Port 80 
               
               
                   
                 HTTPS 
                 Port 443 
               
               
                   
                 SMTP 
                 Port 25 
               
               
                   
                 File Transfer Protocol  
                 Port 21 control, Port 20 data 
               
               
                   
                 (FTP) control and Data 
                   
               
               
                   
                 ICMP 
                   
               
               
                   
                 Telnet 
                 Port 23 
               
               
                   
                 DNS 
                 Port 53 
               
               
                   
                 Network Time Protocol (NTP) 
                 Port 123 (User Datagram  
               
               
                   
                   
                 Protocol (UDP)) 
               
               
                   
                 SSH 
                 Port 22 
               
               
                   
                 Post Office Protocol (POP) 
                 Ports 109/110 
               
               
                   
                 IMAP 
                 Ports 143/220 
               
               
                   
                 Remote Procedure Call 
                 Port 111 
               
               
                   
                 SNMP 
                 Ports 161 (UDP)/162 (TCP/UDP) 
               
               
                   
                 BGP 
                   
               
               
                   
                 Active Sync 
                   
               
               
                   
                 Secure SMTP (SSMTP) 
                 Port 465 
               
               
                   
                 Secure IMAP (IMAP4-SSL) 
                 Port 585 
               
               
                   
                 IMAP4 over SSL (IMAPS) 
                 Port 993 
               
               
                   
                 Secure POP3 (SSL-POP) 
                 Port 995 
               
               
                   
                   
               
            
           
         
       
     
     The firewall  602  can also support HTTP/HTTPS on non-standard ports through customer definition. 
     § 7.3 Application Support 
     The firewall  602  can provide application signature support, which provides the visibility necessary for administrators to understand the applications running on the network including firewall services and applications. The application signature can detect a set of applications via a compiled signature database. The signatures are grouped into default groups with individual apps added to the appropriate group. A user can define a custom group and define which group an application resides. Signatures for custom applications are user-definable (typically through a Regular Expression (regex) engine). 
       FIG.  9    is a screenshot associated with the firewall  602  illustrating example network services. Specifically, the firewall  602  includes several predefined services based on ports. Further, users can create their own customer services and service groups.  FIG.  10    is a screenshot associated with the firewall  602  illustrates example applications. In an embodiment, the firewall  602  can support thousands of applications (e.g., approximately 1200 applications), covering Peer-to-Peer (P2), Instant Messaging (IM), port evasive applications, streaming media, and other applications. Again, because the firewall  602  is multi-tenant and distributed (e.g., worldwide), new services and applications can be added instantly, across all customers and locations. 
     Referring to  FIG.  11   , in an embodiment, a diagram illustrates a Deep Packet Inspection (DPI) engine  650  for the firewall  602 . The DPI engine  650  is part of or works with the firewall  602  to categorize incoming packets  652  to the firewall  602 . The DPI engine  650  includes application plugins  654 , application ID metadata  656 , and flow processing  658 . The application plugins  654  is configured to receive application updates  660  that can be regularly or periodically provided by the cloud system  500 . Through the application updates  660 , the firewall  602  can support more than the approximately  1200  applications. The application ID metadata  656  provides details on how different applications are detected. The flow processing  658  operates on the incoming packets  652  using the application ID metadata  656  to determine applications associated with the incoming packets  652 . The flow processing  658  identifies the protocol and application behind each IP flow of the packets  652  using stateful inspection and heuristic analysis through the extraction of metadata from protocols (e.g., app info, volume, jitter) and does not require SSL decryption. If the DPI engine  650  cannot classify app traffic, it will be categorized as either TCP, UDP, HTTP, or HTTPS. The DPI engine  650  can provide reporting  672  data to the log  604  as well as receive policy  674  updates. 
     The DPI engine  650  can use various classification methods, including explicit, Protocol Data Signature(s), Port-based classification over SSL, IP protocol number, pattern matching, session correlation, and the like. Explicit classification is at a bottom layer where a protocol is identified by information found in the layer below. For example, the IP protocol includes a field called “protocol” defining the protocol embedded in its payload. The Protocol Data Signature(s) is through a Protocol Data Engine. When parsing the HTTP, SSL, and Real-Time Messaging Protocols (RTMP) protocol headers, the Protocol Data Engine can look at a combination of specific value such as HTTP: Server, HTTP:Uniform Resource Indicator (URI), HTTP:User_agent, RTMP:page_Uniform Resource Locator (URL), SSL:common_name, and classifies the upper protocol using this information. For example, Facebook is classified after seeing an HTTP host matching *.facebook.com or *.fbcdn.net. In an embodiment, the DPI engine  650  was shown to take about 20 packets in order to detect the application. 
     For Port-based classification over SSL, in order to classify flows on top of SSL, the TCP port can be used in order to differentiate HTTPS, IMAPS, POP3, etc. For example, POP3 is classified in the SSL TCP port  995 . For IP protocol number, this is a subset to the explicit classification for protocols above IP. As described above, protocols above IP are explicitly specified in the IP protocol. For pattern matching, content parsing is used to identify the protocol. For example, the pattern matching searches for multiple patterns such as HTTP/1.[0|1], [GET|POST|HEAD|CONNECT|PUT|DELETE], and the like. For session correlation, information is required extracted from another flow in which the other protocol negotiated an IP and port for opening a new flow. For example, FTP-data by itself is only a binary streamed over the network and does not provide any information for classification. The only way to classify it is by using information from the FTP session leading to the opening of this flow in which FTP is specifying the IP and port to use for the ftp_data session. 
       FIG.  13    is screenshots of editing IP groups. Specifically,  FIG.  13    illustrates editing a source IP group and editing a destination IP group. IP groups can be predefined for the internal network and destination IPs. Destination IPs can be configured with IP-based countries and IP categories.  FIG.  14    is screenshots of editing a network service. The firewall  602  can include editing HTTP and HTTPS network services to include non-port 80/443 ports, including configured ports that are not used in other services. 
     § 8.0 Policy 
     A firewall policy (or rule) is an exact description of what the firewall  602  is supposed to do with particular traffic. When enabled, the firewall  602  always have at least one active rule, although usually multiple rules are employed to differentiate traffic varieties by {source, destination, and application} and treat them differently. In general, firewall policy consists of matching criteria, an action, and some attributes: 
     rule_rank rule_label [who] [from] [to] [network service] [network application] [when] action [action restrictions] [rule status] [logging] 
     The firewall  602  supports a policy construct, to determine where firewall policy is enforced during an overall order of operation of packet flow through the cloud node  502 . In an embodiment, there are three types of policy, namely, firewall policy, NAT policy, and DNS policy. 
     The firewall policy construct supports a rule order, status, criteria, and action. Policies are matched in the rule order in which they were defined. The status is enabled or disabled. The matching criteria can include the following: 
     
       
         
           
               
               
             
               
                   
               
             
            
               
                 From 
                 Location, Department, Group, IP Address, IP Address  
               
               
                   
                 Group, IP address Ranges, User, and/or User Group 
               
               
                 To 
                 IP address, Address Group, Domain Name or countries 
               
               
                 Firewall  
                 L4 services as listed above, and new services may be  
               
               
                 service(s) 
                 defined by Source IP, Destination IP, Source Port,  
               
               
                   
                 Destination Port, and Protocol 
               
               
                 Firewall  
                 L7 application supported by a Deep Packet Inspection  
               
               
                 application(s) 
                 (DPI) engine 
               
               
                 When 
                 Schedule 
               
               
                 Daily quota 
                 Time or bandwidth, allowing the user to configure  
               
               
                   
                 the amount of time or bandwidth a user is allowed  
               
               
                   
                 for a certain application. 
               
               
                 Action 
                 Allow or block by either dropping traffic or by  
               
               
                   
                 sending TCP reset 
               
               
                   
               
            
           
         
       
     
     All components of the matching criteria are optional and if skipped imply “any.” A session matches a rule when all matching criteria components of the rule are satisfied (TRUE) by the session. If a session matches any element of a component (i.e., one of the IPs in a group), then the entire component is matched. 
     A rule might be configured as either company-wide or restricted to up to a certain number of locations, or up to a certain number of departments, or up to a certain number of users. Some rules might extend their coverage to the entire cloud (SNAT or tracking rules), applying to every company in the cloud. Source/destination IPs are a group of the following in any number/combination. It is used to match session source/destination IPs: • individual IP, i.e. 192.168.1.1; • IP sub-net, i.e. 192.168.1.0/24; • IP range, i.e. 192.168.1.1-192.168.1.5. Note that there is no special support for IP range exclusions; •IP category. Same as the URL category and comes from a database. Custom categories are supported. Applicable to destination IPs only; * country-matches any IP that belongs to this country, i.e., “Russia.” Applicable only to destination IPs; • domain name—any destination IPs behind this name matches this criterion. For example, any IP that matches “skype.com.” The data plane builds an IP cache to match the names from DNS requests coming from the clients. 
     A network service is a group of {TCP/UDP, {src/dst port(s), or port ranges, or port sets} } or just ICMP. Network service defines an application based on L3/L4 information of the first packet in a session. Following is restrictions and implementation details: Each network service can be identified either by its name (aka label) or invisible for customer slot number in the range from 0 to 127. The slot number is required for firewall logging. Following slot numbers are reserved to simplify data plane implementation: 0 - predefined customizable HTTP service group; • 1—predefined customizable HTTPS service group; • 2—predefined customizable DNS service group; • 3-5—reserved for future use; • 6—ICMP any. This service covers ANY ICMP traffic; • 7—UDP any. This service covers ANY UDP traffic-port from 0 to 65535; •8—TCP any. This service covers ANY TCP traffic—port from 0 to 65535; • 63 —OTHER. This service covers all network services that don&#39;t match any predefined or custom services. Basically, it will catch all protocols other than ICMP, UDP, and TCP. • 64—is the very first slot of the custom services. The customer can be allowed to alter (add, modify or delete) protocol and ports in all predefined services except ICMP any, UDP any, TCP any, and OTHER. Although the customer is not allowed to delete a predefined network service, or modify its name, or delete all protocol/port entries in a particular predefined service. Different services must not have overlapping ports for the same protocols. The only exception is predefine *_any services. The data plane chooses more specific network service for logging. For example, if the session matches 2 network services TCP any and SSH then SSH is logged for this session. 
     The network application is defined based on L7 info. This is preconfigured for the cloud and comes only from the DPI engine  650 . Rank is the priority of the rule. Rank is needed to resolve conflicts when a session matches more than one rule. The highest priority rule (the least rank number) takes precedence; 
     A Rule&#39;s action defines what should be done with the matching session. There might be several actions required to apply to a single session. For example, the first action lets the session go through (allow), a next action tells of tracking the session using state-full TCP proxy, next is to apply source NAT to the session, and final action redirects the session to a preconfigured IP. All these different actions belong to different rules. In other words, if the firewall  602  can apply up to 4 different actions to a single session, it&#39;s required to fetch up to 4 different policies for that session. To minimize the number of rules shown to the user front end might want to plump different rule types into a single rule as far as matching criteria are the same for those rules. 
     Here are example supported types of policies categorized by action type: • filtering policies—to allow or block sessions; • tracking policies—tell how to track allowed sessions—statefully or statelessly; • SNAT policies-dictate how to apply source NAT; • DNAT policies—configures destination NAT; • bandwidth control policies; • DNS policies—provide DNS-specific actions. Tracking, SNAT and DNAT policies must be enforced at the first packet. Hence, they do not support network application matching component since its evaluation takes several packets. Action restrictions allow to modify rule action depending on some dynamic info. For example, the customer might want to limit total time or bytes per day of youtube.com traffic. 
     Depending on the action there are different types of rules. The following types can be supported: • filtering rules are evaluated first. Monitored rule status overrides (only) filtering rules action—makes it allow without any restrictions. This type of rule is user-configurable. They provide the following actions: • allow- pass to the evaluation of other types of rules. This action might have an additional restriction for daily time/bandwidth quota; • block_drop-silently drop all packet that matches the rule; • block_reset—for TCP sessions send TCP reset to the client. For non-TCP traffic act the same as block_drop; and block_icmp-response to the client with ICMP error message type 3 (Destination unreachable), code 9 or 10 (network/host administratively prohibited). 
     Tracking rules provide- state-full or stateless action. Only OPs configure this type of rules; they are hidden from the user. The granularity of who component in the matching criteria should be from user to cloud wide. 
     SNAT rules dictate which type of outbound IP should be used for all the traffic matching such rule. Two types of outbound IPs are supported - open and secure. SNAT rules are applied to all outbound traffic, and there is no way to disable it. These rules might be configured by OPs only. The only purpose of SNATrules is to isolate harmful traffic from the rest of the clients. Requires persistence on the node  110 . The granularity of who component in the matching criteria should be from user to cloud wide. 
     DNAT (redirect) rules provide destination IP and port (as the action attribute). They tell where the client-side traffic has to be redirected. Port is optional and when is not specified firewall does not alter destination port. DNAT is user-configurable. 
     A Rule&#39;s attributes include: • rule rank-reflects the priority of the rule comparing to the other rules; • rule label- rule specific label (or name) which is shown in firewall reports. This is a way to match configuration and reporting; • rile status-administrative status of the rule—enabled, disabled, or monitor; • logging- tells how to log sessions created via this rule. 
     The NAT policy construct includes source NAT and destination NAT. For the source NAT, all applications including custom defined applications are NAT&#39;ed with a public IP address associated with the cloud system  500  (source NAT&#39;ed). All return traffic is received and sent back to the appropriate IPsec or GRE tunnel. It may be desirable from an operations perspective to have a different IP address for firewall source NAT&#39;d traffic that for HTTP(S) source NAT&#39;d traffic. This is to avoid blacklists between the two functionalities, so the firewall  602  customers do not accidentally blacklist our HTTP only customers. For destination NAT (DNAT), in cases where the customer wants to force a protocol out a particular port DNAT will be required. 
     The DNS policy construct includes the following: 
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 To 
                 IPs and countries 
               
               
                   
                 IP/domain category 
                 Group of IP or domain categories derived 
               
               
                   
                 Network service 
                   
               
               
                   
                 Network application 
                   
               
               
                   
                 Action 
                 Allow, block, redirect request (to a different  
               
               
                   
                   
                 DNS server or substitute IP in response with  
               
               
                   
                   
                 pre-configured IP) 
               
               
                   
                   
               
            
           
         
       
     
     DNS might be policed on the session as well as on transaction (individual request) levels. While session DNS policies have regular policy structure, the DNS transaction policies are different: 
     rule_label [who] [from] [to] [IP/domain category] [when] action [action restrictions] [rule status] [logging] 
     The differences are: • to- a group of IPs and countries. Note that IP categories should not be included here to avoid confusion. These are IPs or countries of the destination DNS server; • IP/domain category- a group of IP or domain categories derived from ZURL DB. These categories are derived from matching the DNS request domain or responded IP a database. Such separation of to (server IP) and IP/domain category allows to configure fine granular matching criteria like “malicious IP/domain request sent to specific DNS server”; • network service—is not configurable here because DNS transaction policies get applied only to the sessions that matched predefined DNS service group; • network application—is not configurable. There is no way to find an application just by IP (w/o port/protocol). This finds out the application when a client comes with a session using a resolved IP as destination IP. Besides URL category lookup does not return application ID. The application requires one extra look up; • action—actions applied only to DNS transactions. It includes allow, block, redirect_request (redirect to a different DNS server), redirect_response (substitute IP in response with preconfigured IP). Rules with redirect_request action can be applied only to the request phase of DNS transaction. Rules with redirect_response action are applicable only to the response phase of DNS transaction. And finally, rules with allow or block actions are evaluated during both phases (request and response) of DNS transaction. 
     The firewall  602  can support various policies, e.g., 128 policies, 1024 policies, etc., including variable locations, departments, and users per policy. Again, since the firewall  602  is multi-tenant, policies can be different for each customer as well as different for different locations, departments, and users per customer. For user-based policy, a specific user must have IP surrogation enabled for user tracking.  FIG.  12 A  is a screenshot of defining a firewall filtering rule. The rule is named, has an order and rank, and is enabled/disabled. Matching criteria are set for the users, groups, departments, locations—Who, From, To, Network Service, Network App, When. Finally, the action is determined—Allow, Block/Drop, Block with ICMP Error Response, Block with TCP Reset.  FIG.  12 B  is another screenshot of defining a firewall filtering rule. Network service and network application criteria in the same rule results in a logical “AND” condition. In  FIG.  12 B , a Telnet network service on Port 23 and a Telnet network application on any port—“AND” results in telnet protocol as detected by the DPI engine  650  must be on port 23. Conversely, criteria within the same network service or network app are logical “OR.” 
     Referring to  FIG.  15   , in an embodiment, a flow diagram illustrates packet flow through the cloud node  502 . Again, all traffic  680  between users and the Internet  504  is processed through the cloud node  502  (or the processing node). The traffic  680  can be received at a Location Based (LB) instance  682  which could also receive traffic from GRE, a Virtual IP (VIP) IPsec, an LB VIP, etc. From the LB instance  682 , the traffic  680  is sent to one or more instances  684 ,  686 ,  688  (labeled as instance #1, #2, #3). For illustration purposes, the instance  686  is shown which includes a firewall engine  690 , a Web engine  692 , and a policy engine  694 . The firewall engine  690  forwards on port 80/443 traffic to the policy engine  694  and port 80/443 traffic to the Web engine  692 . If Web policy and FW policy are configured for a Web application, Web policy is applied first and then FW policy will be enforced. The policy engine  694  is configured to enforce Web and firewall policies and to send the traffic  680  to the Internet  504 . 
     Referring to  FIG.  16   , in an embodiment, a flowchart illustrates a process  700  for packet flow through the firewall  602  from a client. The process  700  includes receiving a packet (step  702 ). If the packet is from a tunnel (step  704 ), the packet is de-encapsulated (step  706 ) and the process  700  returns to step  702 . After step  704 , a firewall session lookup is performed (step  708 ). If no firewall session exists, the process  700  checks if the packet is location based (step  710 ). If the packet is not location based (step  710 ) and not port 80/443 traffic (step  712 ), the traffic is dropped (step  714 ). If the packet is location based (step  710 ), the process  700  checks if the packet is destined for the cloud node  502  (step  716 ) and if so, moves to step  712 . If the packet is not destined for the cloud node  502  (step  716 ), the process  700  includes creating a firewall session (step  718 ). After step  718  and if a firewall session exists in step  708 , the process  700  checks if the traffic is port  80 / 443  (step  720 ), and if so, established a web proxy (step  722 ). After steps  716 ,  722 , the process  700  checks if the location firewall is enabled (step  724 ). If so, the traffic is processed by the firewall engine  690 , and if not, the traffic is NAT&#39;d (step  726 ). The firewall engine  690  analyzes the traffic through a network services/DPI engine (step  728 ), applies firewall policy (step  730 ), and the traffic is NAT&#39;d (step  726 ). Finally, the packet is sent (step  732 ). 
     Referring to  FIG.  17   , in an embodiment, a flowchart illustrates a process  750  for packet flow through the firewall  602  from a server. The process  750  includes receiving a packet (step  752 ), and a firewall session lookup is performed (step  754 ). If no session exists, the process checks if the traffic is port  80 / 443  (step  756 ), and if not, drops the traffic (step  758 ). If the traffic is port  80 / 443  (step  756 ), a firewall session is created (step  760 ) and a Web proxy is performed (step  762 ). The process  750  checks is location firewall is enabled (step  764 ). If so, the traffic is processed by the firewall engine  690 , and if not, the traffic is NAT&#39;d (step  766 ). The firewall engine  690  analyzes the traffic through a network services/DPI engine (step  768 ), applies firewall policy (step  770 ), and the traffic is NAT&#39;d (step  766 ). Finally, the packet is sent (step  772 ). 
     Every packet hits the firewall  602  which requires the firewall  602  to process packets as efficiently as possible. This is achieved by having slow and fast paths for packet processing. The slow path deals with the very first packet of a new session. It is slow because the corresponding policy has to be found and firewall resources allocated (memory, ports, etc.) for the session. All packets of an existing session go through a fast path where only a simple lookup is required to find the corresponding session. 
     Here is a description of policy evaluation of the first packet in a session—the slow path: 
     • every packet hits the firewall code first—it is intercepted on the ip_input( )level;
 
• if the packet destined to one of the cloud system  500 &#39;s IP addresses, a pass up session is created, and the packet is forwarded up to the network stack. No firewall policy is evaluated in this case;
 
• the who component of matching criteria is evaluated based on a combination of:
         client IP- inner IP in case of a tunnel or just client IP in case of L2 redirection; o tunnel info—outer IP of the tunnel;   default location IP if auth default location ip is configured to 0 value in sc.conf. This IP is used as location IP and overrides any tunnel info;
 
• based on the who value the following actions might be taken:
   if the packet came for a road warrior (no location is found for the client&#39;s IP) and status was ready at least once, then pass up this session.   the packet came from a known location. If firewall functionality is disabled for the company- a pass up session is created, and the packet gets forwarded to the networks stack.;   if the firewall is not configured for the location, a new session object gets created with allow the action, and the packet are SNATed out. The session is allowed to overcome rule infrastructure limitation of only up to 8 locations per rule—the i.e. company wants to disable FW in 100 locations out of 10000. Otherwise, firewall policy evaluation continues;   if the firewall fails to retrieve company, location or user configuration due to lack of resources (out of memory), then the packet is silently dropped. If config retrieval failure is due to any other reason then the cloud wide default policy is applied to the session;   finally, if the firewall is configured for the client, and all configuration is available the session is treated per configured policies;
 
• for policy lookup, firewall queries the configuration of the corresponding company, location, location user, and if available surrogate IP user. Company config contains a list of all firewall rules. The location has the firewall enable/disable knob. And the two users configs tell which firewall rules are enabled for the particular location and particular surrogate IP user.
 
• policy lookup is done to find the highest priority best-matching rule using all enabled rules for the location OR surrogate IP user. In other words, policy lookup evaluated all rules enabled for the location as well as for the surrogate IP user. Note that if a user belongs to a company A while coming to the node  110  from the location of company B, then only location configured policies are applied to such user;
 
• to determine network application (which mostly comes from layer 7) DPI engine usually has to see more than one packet. That is why all filtering rules with “other-than-any” network application components are replaced with similar rules where network application is any and action is allowed. Based on the result of the policy look up firewall creates a session object and acts accordingly. For example, a rule from_subnet_1 network_application_tor DENY for the first look up gets replaced with from_subnet_1 network_application_any ALLOW;
 
• when several packets later network application are determined by DPI, it notifies firewall about the findings. At this point, the firewall checks the original (non-modified) policies and if needed, can correct actions applied to the session. Using the previous example, the DENY rule will be checked during this second policy look up.
       

     Again, all traffic is inspected through the cloud node  502 . Web Traffic (Port 80/443) is sent to the Web Policy engine  692 . If the firewall (non-port 80/443) is enabled, then all web traffic is sent to the firewall engine  690  for inspection. Firewall traffic is sent to the firewall engine  690  and will go through the firewall policy table. Web policies are inspected first. Firewall policies are enforced after all web policies. If there is a web allow policy, firewall policies are still evaluated. 
       FIG.  18    is a screenshot of creating firewall policies. The policies have an order, rule name, criteria, and action. Firewall policies start by defining the Network Services to Allow followed by Network Applications. A basic policy is defined to allow HTTP, HTTPS, and DNS traffic just before the default rule. Again, it may take up to 20 packets in order for the DPI engine  650  to detect the Application. If a packet hits a Network Application policy, and the DPI engine  650  cannot determine the Application, then the packet is allowed, and the next rule is not evaluated. The next rule will be evaluated once the Application is determined. 
       FIG.  19    is a screenshot of a NAT configuration. The firewall  602  can support destination NAT to redirect traffic to another IP and/or port. The use case is to control what resources a user can access. For example, a customer requires their users to go to an internal IP to access external non-web servers. 
       FIG.  20    is a screenshot of a user authentication screen. The user authentication can leverage existing authentication infrastructure in the systems  100 ,  500 . In an embodiment, IP Surrogate is configured to map the IP address to the user. The user must authenticate with the Web first (or have a cookie stored). 
       FIG.  21    is a screenshot of DNS policy. For example, the use case can include guest wireless where a sub location is created for a guest wireless to apply DNS-based policies. DNS policy includes an ability to apply policy based on DNS request - allow, block or redirect the request, redirect response. The DNS policy can be based on server IP or requested/resolved IP category. 
     § Reporting and Logging 
     The firewall  602  can support the log  604 . In an embodiment, the log  604  can be through the logging nodes  140 . The log  604  can be configurable. For example, by default, only blocked events or DNS events are logged. Aggregated logs can be used when logging exceeds certain thresholds or when large amounts of logs need to be processed and is of similar traffic type. For example, Internet Control Message Protocol (ICMP) logs will only be logged until a certain threshold, e.g., 10/second, and then no additional logs will be sent until the traffic falls back under the threshold. The definition of the thresholds for firewall sessions can be defined. 
     Each firewall rule can be configured for full or aggregated logging. Full logging can be enabled by default on block policies. Aggregate logging can be the default on for Allow rules. Allow rules can have the option to be changed to Full logging. In another embodiment, two types of log formats are enabled per rule—i) Full Session logging—performed for all block firewall policies+DNS transactions, and ii) Hourly (or Aggregate) logging—performed for Web logs to avoid duplication with Web transactions. 
     A log format for the log  604  for firewall logs can include: 
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                   
                 Firewall instance ID 
               
               
                   
                   
                 Session Duration 
               
               
                   
                   
                 Time Stamp 
               
               
                   
                   
                 User 
               
               
                   
                   
                 Department 
               
               
                   
                   
                 Location 
               
               
                   
                   
                 Incoming Source IP 
               
               
                   
                   
                 Incoming Destination IP 
               
               
                   
                   
                 Incoming Source Port 
               
               
                   
                   
                 Incoming Destination Port 
               
               
                   
                   
                 Outgoing Source IP 
               
               
                   
                   
                 Outgoing Destination IP 
               
               
                   
                   
                 Outgoing Source Port 
               
               
                   
                   
                 Outgoing Destination Port 
               
               
                   
                   
                 Matched firewall rules 
               
               
                   
                   
                 Firewall service 
               
               
                   
                   
                 Firewall application 
               
               
                   
                   
                 Action (Allow, block) 
               
               
                   
                   
                 Client TX Bytes (from client to firewall 602)-Outbound 
               
               
                   
                   
                 Client RX Bytes (from firewall 602 to the client)-Inbound 
               
               
                   
                   
                 GRE or VPN 
               
               
                   
                   
                 IP Category 
               
               
                   
                   
                 Cloud node 502 ID 
               
               
                   
                   
               
            
           
         
       
     
     A log format for the log  604  for DNS Request/Response logs can include: 
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                   
                 Log Number 
               
               
                   
                   
                 Time 
               
               
                   
                   
                 User 
               
               
                   
                   
                 Department 
               
               
                   
                   
                 Location 
               
               
                   
                   
                 Source IP 
               
               
                   
                   
                 Destination IP 
               
               
                   
                   
                 Query Domain 
               
               
                   
                   
                 IPs 
               
               
                   
                   
                 Category 
               
               
                   
                   
               
            
           
         
       
     
     A log format for the log  604  for Attack logs can include: 
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                   
                 Port Scan 
               
               
                   
                   
                 Syn Flood 
               
               
                   
                   
                 Tear Drop 
               
               
                   
                   
                 ICMP Flood 
               
               
                   
                   
                 UDP Flood 
               
               
                   
                   
                 WinNuke 
               
               
                   
                   
                 Etc. 
               
               
                   
                   
               
            
           
         
       
     
     The purpose of the reports is primarily two-fold, namely i) to provide visibility into the top Applications and Services that are traversing the network and ii) to provide visibility into top firewall threats that have been detected. Note, because the firewall  602  is multi-tenant and distributed (e.g., worldwide), the visibility can be used to detect zero-day/zero-hour threats and instantly provide a defense. 
     Several reports can be supported to display the various fields above in columns that can be configured to be visible or hidden in the display. The reports can be available based on a number of sessions or bytes. The admin can have the ability to filter based on the various fields. The filter can allow the admin (or other users) to show all sessions for a defined between for a particular user, IP address (Source or Destination), or group of IP addresses. There can be two types of reports: Real-time reports generated by Compressed Stats and Analyze reports generated by full session log analysis. Each report below is marked as (RT) Real-Time or (Analyze). Example reports can include Firewall Usage Trend, Top firewall Applications (based # of sessions and bytes)—Includes Applications detected over HTTP, HTTPS (RT), Top Blocked Rules Hit (RT), Top Internal Source IPs (Analyze), Top Destination IPs (Analyze), Top Users (RT), Top Departments (RT), Top Locations (RT), List of Top Users/Departments/Locations with Top Protocols for each User/Dept/Location, List of Top IPs with Top protocols per IP, Top firewall Attacks (Analyze), etc. 
       FIG.  22    is a screenshot of a reporting screen for firewall insights.  FIG.  23    is a screenshot of an interactive report for firewall insights.  FIG.  24    is a screenshot of a graph of usage trends through the firewall  602 .  FIG.  25    is graphs of top firewall protocols in sessions and bytes. 
     In an embodiment, a multi-tenant cloud-based firewall session logging method performed by a cloud node includes firewall Session Stats logging where are a firewall module records aggregated statistics based on various criterion such as client IP, user, network application, location, rule ID, network service, etc., firewall Session Full logging where the firewall module records complete criterion such as user location, network application, customer location, rule ID, network service, client IP, etc. based on every session, and the firewall module implements Rule based choice of logging as described herein. 
     In another embodiment, a multi-tenant cloud-based firewall with integrated web proxy method is performed by a node in the cloud. Firewall traffic which is determined to be web traffic (default port 80/443) is sent through the web proxy prior to being processed by the firewall engine or non-web traffic (default non-port 80/443) traffic. Non-web traffic is processed by the firewall engine bypassing the web proxy engine. Rule order precedence of web traffic processed through the web proxy policies before being processed by firewall policies. The firewall module integrated web proxy could reply End User Notification pages if user traffic hits policies with action block. 
     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, digital signal processors, customized processors, and field-programmable gate arrays (FPGAs) and unique stored program instructions (including both software and firmware) that control the one or more processors 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. Of course, a combination of the aforementioned approaches may be used. Moreover, some embodiments may be implemented as a non-transitory computer-readable storage medium having computer-readable code stored thereon for programming a computer, server, appliance, device, etc. each of which may include a processor to perform methods 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, the software can include instructions executable by a processor that, in response to such execution, cause a processor or any other circuitry to perform a set of operations, steps, methods, processes, algorithms, etc. 
     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.