Patent Publication Number: US-2005131876-A1

Title: Graphical user interface for capture system

Description:
PRIORITY AND RELATED APPLICATIONS  
      This patent application is related to, incorporates by reference, and claims the priority benefit of U.S. Provisional Application 60/528,632, entitled “GRAPHICAL USER INTERFACE FOR DATA CAPTURE AND ANALYSIS SYSTEM”, filed Dec. 10, 2003. 
    
    
     FIELD OF THE INVENTION  
      The present invention relates to computer networks, and in particular, to a graphical user interface for a capture system.  
     BACKGROUND  
      Computer networks and systems have become indispensable tools for modern business. Modern enterprises use such networks for communications and for storage. The information and data stored on the network of a business enterprise is often a highly valuable asset. Modern enterprises use numerous tools to keep outsiders, intruders, and unauthorized personnel from accessing valuable information stored on the network. These tools include firewalls, intrusion detection systems, and packet sniffer devices. However, once an intruder has gained access to sensitive content, there is no network device that can prevent the electronic transmission of the content from the network to outside the network. Similarly, there is no network device that can analyse the data leaving the network to monitor for policy violations, and make it possible to track down information leeks. What is needed is a comprehensive system to capture, store, and analyse all data communicated using the enterprises network.  
     SUMMARY OF THE INVENTION  
      In one embodiment, objects captured over a network can be queried using a graphical user interface. In one embodiment, the graphical user interface (GUI) includes a search editor to enable a user to author and edit a search that mines objects captured by a capture system. In one embodiment, the graphical user also includes a capture rule editor a to enable a user to author and edit a capture rule used by the capture system to intercept objects transmitted over a network.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like reference numerals refer to similar elements and in which:  
       FIG. 1  is a block diagram illustrating a computer network connected to the Internet;  
       FIG. 2  is a block diagram illustrating one configuration of a capture system according to one embodiment of the present invention;  
       FIG. 3  is a block diagram illustrating the capture system according to one embodiment of the present invention;  
       FIG. 4  is a block diagram illustrating an object assembly module according to one embodiment of the present invention;  
       FIG. 5  is a block diagram illustrating an object store module according to one embodiment of the present invention;  
       FIG. 6  is a block diagram illustrating an example hardware architecture for a capture system according to one embodiment of the present invention;  
       FIG. 7  illustrates a login view according to one embodiment of the present invention;  
       FIG. 8  illustrates a home view according to one embodiment of the present invention;  
       FIG. 9  illustrates a statistical view according to one embodiment of the present invention;  
       FIG. 10  illustrates a search view according to one embodiment of the present invention;  
       FIG. 11  illustrates a search editor according to one embodiment of the present invention;  
       FIG. 12  illustrates a mail view of the search editor according to one embodiment of the present invention;  
       FIG. 13  illustrates an images view of the search editor according to one embodiment of the present invention;  
       FIG. 14  illustrates an FTP view of the search editor according to one embodiment of the present invention;  
       FIG. 15  illustrates a search scheduler according to one embodiment of the present invention;  
       FIG. 16  illustrates a results view according to one embodiment of the present invention; and  
       FIG. 17  illustrates a capture rule editor according to one embodiment of the present invention.  
    
    
     DETAILED DESCRIPTION  
      Although the present system will be discussed with reference to various illustrated examples, these examples should not be read to limit the broader spirit and scope of the present invention. Some portions of the detailed description that follows are presented in terms of algorithms and symbolic representations of operations on data within a computer memory. These algorithmic descriptions and representations are the means used by those skilled in the computer science arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consistent sequence of steps leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared and otherwise manipulated.  
      It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers or the like. It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise, it will be appreciated that throughout the description of the present invention, use of terms such as “processing”, “computing”, “calculating”, “determining”, “displaying” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system&#39;s registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.  
      As indicated above, one embodiment of the present invention is instantiated in computer software, that is, computer readable instructions, which, when executed by one or more computer processors/systems, instruct the processors/systems to perform the designated actions. Such computer software may be resident in one or more computer readable media, such as hard drives, CD-ROMs, DVD-ROMs, read-only memory, read-write memory and so on. Such software may be distributed on one or more of these media, or may be made available for download across one or more computer networks (e.g., the Internet). Regardless of the format, the computer programming, rendering and processing techniques discussed herein are simply examples of the types of programming, rendering and processing techniques that may be used to implement aspects of the present invention. These examples should in no way limit the present invention, which is best understood with reference to the claims that follow this description.  
      Networks  
       FIG. 1  illustrates a simple prior art configuration of a local area network (LAN)  10  connected to the Internet  12 . Connected to the LAN  102  are various components, such as servers  14 , clients  16 , and switch  18 . There are numerous other known networking components and computing devices that can be connected to the LAN  10 . The LAN  10  can be implemented using various wireline or wireless technologies, such as Ethernet and 802.11b. The LAN  10  may be much more complex than the simplified diagram in  FIG. 1 , and may be connected to other LANs as well.  
      In  FIG. 1 , the LAN  10  is connected to the Internet  12  via a router  20 . This router  20  can be used to implement a firewall, which are widely used to give users of the LAN  10  secure access to the Internet  12  as well as to separate a company&#39;s public Web server (can be one of the servers  14 ) from its internal network, i.e., LAN  10 . In one embodiment, any data leaving the LAN  10  towards the Internet  12  must pass through the router  12 . However, there the router  20  merely forwards packets to the Internet  12 . The router  20  cannot capture, analyse, and searchably store the content contained in the forwarded packets.  
      One embodiment of the present invention is now illustrated with reference to  FIG. 2 .  FIG. 2  shows the same simplified configuration of connecting the LAN  10  to the Internet  12  via the router  20 . However, in  FIG. 2 , the router  20  is also connected to a capture system  22 . In one embodiment, the router  12  splits the outgoing data stream, and forwards one copy to the Internet  12  and the other copy to the capture system  22 .  
      There are various other possible configurations. For example, the router  12  can also forward a copy of all incoming data to the capture system  22  as well. Furthermore, the capture system  22  can be configured sequentially in front of, or behind the router  20 , however this makes the capture system  22  a critical component in connecting to the Internet  12 . In systems where a router  12  is not used at all, the capture system can be interposed directly between the LAN  10  and the Internet  12 . In one embodiment, the capture system  22  has a user interface accessible from a LAN-attached device, such as a client  16 .  
      In one embodiment, the capture system  22  intercepts all data leaving the network. In other embodiments, the capture system can also intercept all data being communicated inside the network  10 . In one embodiment, the capture system  22  reconstructs the documents leaving the network  10 , and stores them in a searchable fashion. The capture system  22  can then be used to search and sort through all documents that have left the network  10 . There are many reasons such documents may be of interest, including network security reasons, intellectual property concerns, corporate governance regulations, and other corporate policy concerns.  
      Capture System  
      One embodiment of the present invention is now described with reference to  FIG. 3 .  FIG. 3  shows one embodiment of the capture system  22  in more detail. The capture system  22  includes a network interface module  24  to receive the data from the network  10  or the router  20 . In one embodiment, the network interface module  24  is implemented using one or more network interface cards (NIC), e.g., Ethernet cards. In one embodiment, the router  20  delivers all data leaving the network to the network interface module  24 .  
      The captured raw data is then passed to a packet capture module  26 . In one embodiment, the packet capture module  26  extracts data packets from the data stream received from the network interface module  24 . In one embodiment, the packet capture module  26  reconstructs Ethernet packets from multiple sources to multiple destinations for the raw data stream.  
      In one embodiment, the packets are then provided the object assembly module  28 . The object assembly module  28  reconstructs the objects being transmitted by the packets. For example, when a document is transmitted, e.g. as an email attachment, it is broken down into packets according to various data transfer protocols such as Transmission Control Protocol/internet Protocol (TCP/IP) and Ethernet. The object assembly module  28  can reconstruct the document from the captured packets.  
      One embodiment of the object assembly module  28  is now described in more detail with reference to  FIG. 4 . When packets first enter the object assembly module, they are first provided to a reassembler  36 . In one embodiment, the reassembler  36  groups—assembles—the packets into unique flows. For example, a flow can be defined as packets with identical Source IP and Destination IP addresses as well as identical TCP Source and Destination Ports. That is, the reassembler  36  can organize a packet stream by sender and recipient.  
      In one embodiment, the reassembler  36  begins a new flow upon the observation of a starting packet defined by the data transfer protocol. For a TCP/IP embodiment, the starting packet is generally referred to as the “SYN” packet. The flow can terminate upon observation of a finishing packet, e.g., a “Reset” or “FIN” packet in TCP/IP. If now finishing packet is observed by the reassembler  36  within some time constraint, it can terminate the flow via a timeout mechanism. In an embodiment using the TPC protocol, a TCP flow contains an ordered sequence of packets that can be assembled into a contiguous data stream by the ressembler  36 . Thus, in one embodiment, a flow is an ordered data stream of a single communication between a source and a destination.  
      The flown assembled by the reassember  36  can then be provided to a protocol demultiplexer (demux)  38 . In one embodiment, the protocol demux  38  sorts assembled flows using the TCP Ports. This can include performing a speculative classification of the flow contents based on the association of well-known port numbers with specified protocols. For example, Web Hyper Text Transfer Protocol (HTTP) packets—i.e., Web traffic—are typically associated with port  80 , File Transfer Protocol (FTP) packets with port  20 , Kerberos authentication packets with port  88 , and so on. Thus in one embodiment, the protocol demux  38  separates all the different protocols in one flow.  
      In one embodiment, a protocol classifier  40  also sorts the flows in addition to the protocol demux  38 . In one embodiment, the protocol classifier  40 —operating either in parallel or in sequence with the protocol demux  38 —applies signature filters to the flows to attempt to identify the protocol based solely on the transported data. Furthermore, the protocol demux  38  can make a classification decision based on port number which is subsequently overridden by protocol classifier  40 . For example, if an individual or program attempted to masquerade an illicit communication (such as file sharing) using an apparently benign port such as port  80  (commonly used for HTTP Web browsing), the protocol classifier  40  would use protocol signatures, i.e., the characteristic data sequences of defined protocols, to verify the speculative classification performed by protocol demux  38 .  
      In one embodiment, the object assembly module  28  outputs each flow organized by protocol, which represent the underlying objects. Referring again to  FIG. 3 , these objects can then be handed over to the object classification module  30  (sometimes also referred to as the “content classifier”) for classification based on content. A classified flow may still contain multiple content objects depending on the protocol used. For example, protocols such as HTTP (Internet Web Surfing) may contain over 100 objects of any number of content types in a single flow. To deconstruct the flow, each object contained in the flow is individually extracted, and decoded, if necessary, by the object classification module  30 .  
      The object classification module  30  uses the inherent properties and signatures of various documents to determine the content type of each object. For example, a Word document has a signature that is distinct from a PowerPoint document, or an Email document. The object classification module  30  can extract out each individual object and sort them out by such content types. Such classification renders the present invention immune from cases where a malicious user has altered a file extension or other property in an attempt to avoid detection of illicit activity.  
      In one embodiment, the object classification module  30  determines whether each object should be stored or discarded. In one embodiment, this determination is based on a various capture rules. For example, a capture rule can indicate that Web Traffic should be discarded. Another capture rule can indicate that all PowerPoint documents should be stored, except for ones originating from the CEO&#39;s IP address. Such capture rules can be implemented as regular expressions, or by other similar means.  
      In one embodiment, the capture rules are authored by users of the capture system  22 . The capture system  22  is made accessible to any network-connected machine through the network interface module  24  and user interface  34 . In one embodiment, the user interface  34  is a graphical user interface providing the user with friendly access to the various features of the capture system  22 . For example, the user interface  34  can provide a capture rule authoring tool that allows users to write and implement any capture rule desired, which are then applied by the object classification module  30  when determining whether each object should be stored. The user interface  34  can also provide pre-configured capture rules that the user can select from along with an explanation of the operation of such standard included capture rules. In one embodiment, the default capture rule implemented by the object classification module  30  captures all objects leaving the network  10 .  
      If the capture of an object is mandated by the capture rules, the object classification module  30  can also determine where in the object store module  32  the captured object should be stored. With reference to  FIG. 5 , in one embodiment, the objects are stored in a content store  44  memory block. Within the content store  44  are files  46  divided up by content type. Thus, for example, if the object classification module determines that an object is a Word document that should be stored, it can store it in the file  46  reserved for Word documents. In one embodiment, the object store module  32  is integrally included in the capture system  22 . In other embodiments, the object store module can be external—entirely or in part—using, for example, some network storage technique such as network attached storage (NAS) and storage area network (SAN).  
      Tag Data Structure  
      In one embodiment, the content store is a canonical storage location, simply a place to deposit the captured objects. The indexing of the objects stored in the content store  44  is accomplished using a tag database  42 . In one embodiment, the tag database  42  is a database data structure in which each record is a “tag” that indexes an object in the content store  44  and contains relevant information about the stored object. An example of a tag record in the tag database  42  that indexes an object stored in the content store  44  is set forth in Table 1:  
                   TABLE 1                       Field Name   Definition                  MAC Address   Ethernet controller MAC address unique to each           capture system       Source IP   Source Ethernet IP Address of object       Destination IP   Destination Ethernet IP Address of object       Source Port   Source TCP/IP Port number of object       Destination Port   Destination TCP/IP Port number of the object       Protocol   IP Protocol that carried the object       Instance   Canonical count identifying object within a protocol           capable of carrying multiple data within a single           TCP/IP connection       Content   Content type of the object       Encoding   Encoding used by the protocol carrying object       Size   Size of object       Timestamp   Time that the object was captured       Owner   User requesting the capture of object (rule author)       Configuration   Capture rule directing the capture of object       Signature   Hash signature of object       Tag Signature   Hash signature of all preceding tag fields                  
 
      There are various other possible tag fields, and some embodiments can omit numerous tag fields listed in Table 1. In other embodiments, the tag database  42  need not be implemented as a database, and a tag need not be a record. Any data structure capable of indexing an object by storing relational data over the object can be used as a tag data structure. Furthermore, the word “tag” is merely descriptive, other names such as “index” or “relational data store,” would be equally descriptive, as would any other designation performing similar functionality.  
      The mapping of tags to objects can, in one embodiment, be obtained by using unique combinations of tag fields to construct an object&#39;s name. For example, one such possible combination is an ordered list of the Source IP, Destination IP, Source Port, Destination Port, Instance and Timestamp. Many other such combinations including both shorter and longer names are possible. In another embodiment, the tag can contain a pointer to the storage location where the indexed object is stored.  
      The tag fields shown in Table 1 can be expressed more generally, to emphasize the underlying information indicated by the tag fields in various embodiments. Some of these possible generic tag fields are set forth in Table 2:  
                   TABLE 2                       Field Name   Definition                  Device Identity   Identifier of capture device       Source Address   Origination Address of object       Destination Address   Destination Address of object       Source Port   Origination Port of object       Destination Port   Destination Port of the object       Protocol   Protocol that carried the object       Instance   Canonical count identifying object within a protocol           capable of carrying multiple data within a single           connection       Content   Content type of the object       Encoding   Encoding used by the protocol carrying object       Size   Size of object       Timestamp   Time that the object was captured       Owner   User requesting the capture of object (rule author)       Configuration   Capture rule directing the capture of object       Signature   Signature of object       Tag Signature   Signature of all preceding tag fields                  
 
      For many of the above tag fields in Tables 1 and 2, the definition adequately describes the relational data contained by each field. For the content field, the types of content that the object can be labelled as are numerous. Some example choices for content types (as determined, in one embodiment, by the object classification module  30 ) are JPEG, GIF, BMP, TIFF, PNG (for objects containing images in these various formats); Skintone (for objects containing images exposing human skin); PDF, MSWord, Excel, PowerPoint, MSOffice (for objects in these popular application formats); HTML, WebMail, SMTP, FTP (for objects captured in these transmission formats); Telnet, Rlogin, Chat (for communication conducted using these methods); GZIP, ZIP, TAR (for archives or collections of other objects); C++ Source, C Source, FORTRAN Source, Verilog Source (for source or design code authored in these high-level programming languages); C Shell, K Shell, Bash Shell (for shell program scripts); Plaintext (for otherwise unclassified textual objects); Crypto (for objects that have been encrypted or that contain cryptographic elements); Binary Unknown, ASCII Unknown, and Unknown (as catchall categories).  
      The signature contained in the Signature and Tag Signature fields can be any digest or hash over the object, or some portion thereof. In one embodiment, a well known hash, such as MD5 or SHA1 can be used. In one embodiment, the signature is a digital cryptographic signature. In one embodiment, a digital cryptographic signature is a hash signature that is signed with the private key of the capture system  22 . Only the capture system  22  knows its own private key, thus, the integrity of the stored object can be verified by comparing a hash of the stored object to the signature decrypted with the public key of the capture system  22 , the private and public keys being a public key cryptosystem key pair. Thus, if a stored object is modified from when it was originally captured, the modification will cause the comparison to fail.  
      Similarly, the signature over the tag stored in the Tag Signature field can also be a digital cryptographic signature. In such an embodiment, the integrity of the tag can also be verified. In one embodiment, verification of the object using the signature, and the tag using the tag signature is performed whenever an object is presented, e.g., displayed to a user. In one embodiment, if the object or the tag is found to have been compromised, an alarm is generated to alert the user that the object displayed may not be identical to the object originally captured.  
      Graphical User Interface  
      One embodiment of the user interface  34  is a graphical user interface (GUI) described in greater detail with reference to  FIGS. 7-17 . In one embodiment, the GUI enables the user to mine the tag database based on search criteria corresponding to the tag fields. Furthermore, the search criteria can also include other indexed search criteria, such as single dictionary keywords, and non-indexed search criteria, such as word patterns. Thus, in one embodiment, searches (also referred to as mines or queries) can mine both the tag database and the content store.  
      In one embodiment, a user&#39;s identity is verified by requiring a password to log into the system  22 . For example, a user can log on via the logon view  702  shown in  FIG. 7 . In one embodiment, the GUI is configured based on the identity of the user. For example, the username “admin” may belong to the CTO who is only interested in confidential technical documents. The GUI can configure itself to display options relevant to the interests of the CTO.  
      In one embodiment, after logging on, the GUI displays an analyze view  704  to the user. In analyze view, the user can perform analysis on the objects (also sometimes referred to as documents) captured by the capture system  22 . In one embodiment, the GUI also has a setup view  708 , which enables the user to control the operation of the capture system  22 . The names “analyze” and “setup” are merely descriptive, and their functionalities can be given numerous other descriptive names. For example, the analyze view  704  could be called the “research view,” or the “data mining view,” or any other name, so long as the view enables the user to analyze or search or mine or graph the captured objects.  
      In one embodiment, the analyze view  704  includes a home view  706  of the monitored network, illustrated in  FIG. 8 . The home view  706  may include a bar graph or other chart indicating a statistical breakdown of all captured, i.e. intercepted, objects, by object type.  
      In one embodiment, the analyze view  704  also includes a statistics view  708 , illustrated in  FIG. 9 . The statistics view  708  displays a bar graph of the protocols used to transmit the captured objects. Other graphs can be displayed by the statistics view  708 , such as statistical breakdowns of individual users, distributions among users or network segments, and various other statistical data presentation over the captured objects.  
      In one embodiment, the analyze view  704  also includes a search view  710 . In one embodiment, the search view  710  is the tool provided by the GUI to author searches (also referred to as queries or mines), save searches, edit saved searches, schedule searches, and view search results. As illustrated in  FIG. 10 , the search view  710  displays a list of saved searches. Options are available to run  712  (execute) each search, to edit  714  each search, to schedule  716  or edit the scheduling of each search, to delete  718  each search, or to create a new search  720 .  
      In one embodiment, if the user selects his option to create a new search  720  or to edit a saved search  714 , the GUI provides a search editor view  722  to the user, as illustrated by  FIGS. 11-14 . One embodiment of the search editor  722  illustrated by  FIG. 11  is configured to enable the user to create or edit a search for documents. In one embodiment, “documents” is a catchall category for describing objects. The user is provided with various keyword and word pattern search options to specify words and phrases in the stored objects the search is designed to find or avoid. Singe keyword searches may be indexed. Word pattern searches, such as searches for an exact phrase, are generally un-indexed. Thus, in one embodiment, the search editor  722  is configured to input both indexed and non-indexed search criteria to construct a single search.  
      In addition, in one embodiment illustrated by  FIG. 11 , the user can also specify other indexed search criteria, such as source and destination IP and port addresses, and masks, and protocol (e.g., HTTP Post, Response or Webmail Attachment, or SMPT Attachment), to define transmission details of the objects of interest. In one embodiment, the user may also select objects by type by selecting from a list of possible document content types, such as the list of document types described with reference to Tables 1 and 2.  
      The user can further narrow the search by specifying a size range for the objects of interest, and a temporal range for the objects of interest. When the user is finished authoring the search, he can provide a name for the search and save it to the saved searches list shown in  FIG. 10 . When the user selects to edit  714  an existing document search, the search editor  722  has the saved elements already filled in.  
      One embodiment of the search editor  722  illustrated by  FIG. 12  is configured to enable the user to create or edit a search for electronic mail. The user can select the type of mail used to transmit the objects of interest (e.g., WebMail or SMTP mail). The user may then provide origination, destination, carbon copy, and blind carbon copy addresses of the objects of interest. These search criteria may be indexed. The user is also provided with various keyword and word pattern search options to specify words and phrases in the subject and message portions of the e-mail messages of interest. These search criteria may be non-indexed.  
      The user can further narrow the search by specifying a size range for the e-mail of interest, and a temporal range to specify when the e-mails of interest may have been sent. When the user is finished authoring the search, he can provide a name for the search and save it to the saved searches list shown in  FIG. 10 .  
      One embodiment of the search editor  722  illustrated by  FIG. 13  is configured to enable the user to create or edit a search for images. The user is provided with an option to activate a skin tone analyzer for the search. A skin tone analyzer detects images of naked people, and is helpful to catch pornographic images being transmitted on the network. The user can also specify source and destination IP and port addresses, and masks, and protocol, to specify transmission details of the objects of interest. The user may also select the type of image format of interest by selecting from a list of possible image types, such as BMP, GIF, and JPEG.  
      The user can further narrow the search by specifying a size range for the images of interest, and a temporal range for the images of interest. When the user is finished authoring the search, he can provide a name for the search and save it to the saved searches list shown in  FIG. 10 .  
      One embodiment of the search editor  722  illustrated in  FIG. 14  is configured to enable the user to create or edit a search for file transfer protocol (FTP) file transfers. The user can specify source and destination IP addresses and masks for the transfers of interest. The user can also indicate the username of the person who executed the FTP transfer. The user can also proved various transmit and receive keywords of interest in the transfer. These keywords can be indexed or non-indexed.  
      The user can further narrow the search by specifying a size range for the FTP transfers of interest, and a temporal range for the FTP transfers of interest. When the user is finished authoring the search, he can provide a name for the search and save it to the saved searches list shown in  FIG. 10 .  
      In one embodiment, after a search is created, the GUI provides a search scheduler  724 —illustrated by  FIG. 15 —to enable the user to schedule periodic execution of the search. Thus, a user can periodically receive reports from the capture system  22  based on the saved searches. In one embodiment, the GUI directs the user to the scheduling view  724  if the user selects option  716  in  FIG. 10 . In one embodiment, the GUI also directs the user to the search scheduler  724  every time a new search is created using the search editor  722  views illustrated in  FIGS. 11-14 .  
      In one embodiment, illustrated in  FIG. 15 , the search scheduler  724  asks the user to specify a start date and time for the first time the search is to be run. In one embodiment, the user is also provided with several scheduling options to choose from indicating the periodic repetition of the search. For example, a search could be scheduled to execute on an hourly bases. Other preset scheduling options can include, immediately, every half hour, every eight hours, once a day, once a week, once a month, once a year, and so on.  
      In one embodiment, when a search is executed, i.e., run, its results—the stored objects found according to the search parameters—are displayed in a results view illustrated in  FIG. 16 . In one embodiment, the results are listed according to various attributes, such as object type (PDF, Word, PowerPoint, Mail, ect.), content, source and destination address, size, and date captured. The results view  726  can order the results according to any such attribute selected by the user.  
      In one embodiment, the GUI also provides a setup view  730  illustrated in  FIG. 17 . Unlike the analyze view  710  discussed with reference to  FIGS. 8-16  that enable the user to analyze captured objects, the setup view  730  enable the user to change and configure the operation of the capture system  22 . In one embodiment, the setup view  730  includes a capture rule editor  732 , which allows the user to author capture rules used by the system  22  to decide what intercepted objects to index and store.  
      In one embodiment, the capture rule editor  732  provides the user view tools similar to the search editor  722  as illustrated in  FIG. 11 . The user can be provided with various keyword options (not shown) to specify words and phrases that, if they appear in the object, indicate that the object should be captured, i.e., stored. in the stored objects the search is designed to find or avoid. In one embodiment, the user can specify source and destination IP and port addresses, and masks, and protocol, to specify transmission details of the objects the user is interested in capturing. The user may also indicate the types of objects of interest by selecting from a list of possible document types.  
      The user can further craft the capture rule by specifying a size range for the objects of interest, and a temporal range for the objects of interest. When the user is finished authoring the capture rule, he can provide a name for the rule and save it. In one embodiment, after the rule is saved, it affects how the system  22  captures and stores objects until it is deactivated or deleted. A user can later edit saved capture rules using the capture rule editor  730  as well.  
      General Matters  
      In several embodiments, the capture system  22  has been described above as a stand-alone device. However, the capture system of the present invention can be implemented on any appliance capable of capturing and analysing data from a network. For example, the capture system  22  described above could be implemented on one or more of the servers  14  or clients  16  shown in  FIG. 1 . The capture system  22  can interface with the network  10  in any number of ways, including wirelessly.  
      In one embodiment, the capture system  22  is an appliance constructed using commonly available computing equipment and storage systems capable of supporting the software requirements. In one embodiment, illustrated by  FIG. 6 , the hardware consists of a capture entity  46 , a processing complex  48  made up of one or more processors, a memory complex  50  made up of one or more memory elements such as RAM and ROM, and storage complex  52 , such as a set of one or more hard drives or other digital or analog storage means. In another embodiment, the storage complex  52  is external to the capture system  22 , as explained above. In one embodiment, the memory complex stored software consisting of an operating system for the capture system device  22 , a capture program, and classification program, a database, a filestore, an analysis engine and a graphical user interface.  
      Thus, a capture system and a document/content registration system have been described. In the forgoing description, various specific values were given names, such as “objects,” and various specific modules, such as the “registration module” and “signature database” have been described. However, these names are merely to describe and illustrate various aspects of the present invention, and in no way limit the scope of the present invention. Furthermore, various modules, such as the search engine  64  and the notification module  66  in  FIG. 8 , can be implemented as software or hardware modules, or without dividing their functionalities into modules at all. The present invention is not limited to any modular architecture either in software or in hardware, whether described above or not.