Abstract:
A system and method establishes bidirectional contact through firewall devices. A method includes establishing a first connection between a first device and a second device and storing a connection record on the second device. When the second device receives a request to connect with the first device, it identifies and searches for the connection record corresponding to the first device. When the second device finds the connection, the second device sends a request to establish a second connection from the second device to the first device. Upon receiving the request to establish a second connection, the first device verifies the request to establish the second connection and the lifetime of the first connection. Upon verification, the first device establishes the second connection between the first computing device and the second device.

Description:
BACKGROUND 
     Software and hardware recovery can include creating a copy of data. Data copying via a network can require network configuration. Secure transmission of data via a network can require creation of multiple, secure connections. 
     BRIEF SUMMARY 
     According to one aspect of the present disclosure, a method of bidirectional network data replication includes establishing a first connection between a first device and a second device and storing a connection record on the second device. When the second device receives a request to connect with the first device, it identifies and searches for the connection record corresponding to the first device. When the second device finds the connection, the second device sends a request to establish a second connection from the second device to the first device. Upon receiving the request to establish a second connection, the first device verifies the request to establish the second connection and the lifetime of the first connection. Upon verification, the first device establishes the second connection between the first computing device and the second device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Aspects of the present disclosure are illustrated by way of example and are not limited by the accompanying FIGS. with like references indicating like elements. 
         FIG. 1  illustrates forward data replication in a bidirectional data replication system. 
         FIG. 2  illustrates target server site prevention of reverse data replication in a bidirectional data replication system. 
         FIG. 3  illustrates an example first and second bidirectional network connection. 
         FIG. 4  illustrates an example flowchart for creating a bidirectional network connection. 
         FIG. 5  illustrates an example of a computer system to implement techniques. 
     
    
    
     DETAILED DESCRIPTION 
     Software and hardware recovery (e.g., restoration) can include creating a copy (e.g., replication) of data. The data may include executable files (e.g., binary files), configuration files, or other data files. Software that enables data replication or high-availability (e.g., ARCServe RHA) can require frequent data replication, and frequent data replication can require a reliable connection between a replica server and a target server (e.g., server on customer site). However, connectivity cannot be assured in all environments, as firewalls or other network security measures can interfere with connectivity. For example, a customer may need to restore data from a server (e.g., remote server, an internet-based “cloud” server, or a local server) behind a firewall. 
     An advantage of one or more of the methods discussed herein can include avoiding a need to change a network configuration on a customer&#39;s site. Another advantage can include increased security. For example, because the NAT connections are built from target servers on customer&#39;s site, only authenticated servers on the public network can access the target servers through these connections, and is therefore more secure than configuring IP/port forwarding for target servers. Yet another advantage can include facilitating support for disaster recovery or backward data replication from the replica server or internet-based servers to the target servers on customer&#39;s site. 
       FIG. 1  illustrates forward data replication in a bidirectional data replication system  100 , according to an embodiment. The bidirectional data replication system can include a target server site  110 , a replica server site  120 , or an internet server site  130 . A target server site  110  can include one or more on-premise servers  112  and  114 . A replica server site  120  can include one or more replica site replica servers  122  and  124 . An internet server site  130  can include one or more internet site replica servers  132  and  134 . 
     Forward data replication  140  occurs when an on-premise server (e.g., on-premise server  112 ) can access a public network (e.g., the internet  150 ), and the on-premise server  112  creates a direct connection to the replica server site  120  or the internet server site  130 . For example, on-premise server  114  can create a direct connection to replica server  134 . A server site can include a firewall (e.g., target server site firewall  116  or replica server site firewall  126 ) or other mechanism to filter network traffic. For example, a server site can block all network connection ports except for hypertext transfer protocol (HTTP) ports, or a server site can block certain port numbers. To enable a connection through a network with blocked ports, the receiving network can be configured for port forwarding (e.g., routing traffic from one incoming port to a different internal port). Using port forwarding, a server site can receive data from a remote server and forward the data to a local server. For example, on-premise server  114  can create a connection to the replica server site  120 , and the replica server site  120  can forward the data to replica server  124 . 
       FIG. 2  illustrates prevention of reverse data replication in a bidirectional data replication system  200 , according to an embodiment. Prevention of reverse data replication  240  can occur when data is available for replication on the replica server site  120  or internet server site  130 , but the replica server site  120  or internet server site  130  is unable to connect to the target server site  110 . For example, replica server  124  may be able to access the internet  150  through a replica server site firewall  126  to create a request to begin reverse data replication  240 , but the reverse data replication  240  may be blocked by a target server site firewall  116 . 
       FIG. 3  illustrates an example first and second bidirectional network connection  300 , according to an embodiment. To enable data replication, data must first be backed up from the target server site  110  to a replica server site  120  or to an internet server site. For example, a target server site on-premise server  114  can back up data to a replica server site replica server  124 . During the backup phase, a first connection  310  can be made from the target server site  110  to a replica server site  120 . The first connection  310  can use Transmission Control Protocol and Internet Protocol (TCP/IP). When a TCP/IP connection is created, the first connection TCP/IP connection information can be stored, and the bidirectional network connection  300  can use the stored TCP/IP connection information. The list of TCP/IP connection information can include a mapping of local connection parameters to remote connection parameters, which can be stored in a network address translation (NAT) table. As discussed above, port forwarding can be used to create one or more connections between the replica server site  120  and the target server site  110 , but port forwarding can reduce network security. As an alternative to port forwarding, a second, bidirectional network connection can be made to connect the target server site  110  and the replica server site  120 . 
     To create the first connection  310 , the on-premise server  114  sends a request to initiate a connection  320  with the replica server  124 . The first connection  310  can be encrypted. The first connection  310  can have an associated lifetime, after which the first connection  310  will end automatically. After the first connection  310  has been established, the on-premise server  114  can check the first connection  310  periodically to see if the lifetime has expired. If on-premise server  114  identifies that the lifetime of the first connection  310  has expired, the on-premise server  114  can use the first connection TCP/IP connection information stored in the NAT table to reestablish the first connection  310  with the replica server  124 . 
     Once the first connection  310  is established, the on-premise server  114  begins forward replication  140  with the replica server  124 . After the forward replication  140  has been completed, the replicated information is available at the replica server  124  for reverse replication (i.e., to be transferred back) to the on-premise server  114  or to a different server. The network configuration (e.g., firewalls) between the on-premise server  114  and the replica server  124  may prevent reverse replication initiated at the replica server  124 . To enable reverse replication initiated at the replica server  124 , a new connection can be created and used to transfer replicated information. A transfer of replicated information can be initiated on the replica server  124  by receiving a command from a requestor, where the requestor can be a user or an application on the replica server  124 . A transfer of replicated information can be initiated on the replica server  124  by receiving a command to transfer replicated information from the on-premise server  114 . Once a transfer of replicated information has been initiated, the replica server  124  can send a request to create a new connection  330  from the replica server  124  to the on-premise server  114 . The on-premise server  114  can process the request and send a request to initiate a new connection  340 , which can become the second connection  350 . The second connection  350  can be encrypted. Once the replica server  124  and the on-premise server  114  establish this second connection  350 , the reverse replication process  240  can begin. To improve security, the second connection  350  can be closed after the completion of the reverse replication  240 . 
       FIG. 4  illustrates an example flowchart of searching for and creating a bidirectional network connection  400 , according to an embodiment. A bidirectional network connection can be created to enable reverse replication, as discussed above. Creating a bidirectional network connection can include creating a new TCP/IP connection  410 . When a data restoration event has been initiated, the replica server can search for the TCP/IP connection within the list of TCP/IP connections stored in the NAT table  420 . If the TCP/IP connection is not found in the NAT table, then replica server can attempt to create a direct TCP/IP connection  430 , and can return the connection information to the replication service  440 . The new TCP/IP connection can be encrypted. The direct connection may fail, for example, due to a firewall preventing the connection. If the direct connection fails, the replication system will notify the user of the failed connection. 
     If the TCP/IP connection is found in the NAT table, then the replica server can send a request to create a new connection via the TCP/IP connection  450  to the target server. When the target server receives a new request  455 , it can create the TCP/IP connection and send it to the replica server  460 . When the replica server receives the TCP/IP connection, it can add the TCP/IP connection information to the NAT table  465 . The replica server can periodically check the NAT table for a connection for the target server  470 , and when the replica server can identify a connection for the target server in the NAT table, it can get the matched connection information  480 , and return the connection information to the replication service  440 . 
       FIG. 5  shows a block diagram of an example of a computer system to implement various embodiments. In the embodiment shown in  FIG. 5 , a hardware and operating environment is provided that is applicable to any of the embodiments described. As shown in  FIG. 5 , the hardware and operating environment can include a general purpose computing device in the form of a computer  500  (e.g., a personal computer, workstation, or server), including one or more processing units  521 , a system memory  522 , or a system bus  523  that operatively couples various system components including the system memory  522  to the processing unit  521 . There can be one or more one processing units  521 , such that the processor of computer  500  comprises a single CPU, or a plurality of processing units, commonly referred to as a multiprocessor or parallel-processor environment. In one or more embodiments, computer  500  is a conventional computer, a distributed computer, or any other type of computer. 
     The system bus  523  can be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. The system memory can also be referred to as simply the memory, and, in some embodiments, includes read-only memory (ROM)  524  and random-access memory (RAM)  525 . A basic input/output system (BIOS) program  526 , containing the basic routines that help to transfer information between elements within the computer  500 , such as during start-up, can be stored in ROM  524 . The computer  500  can further include a hard disk drive  527  for reading from and writing to a hard disk, not shown, a magnetic disk drive  528  for reading from or writing to a removable magnetic disk  529 , and an optical disk drive  530  for reading from or writing to a removable optical disk  531  such as a CD ROM or other optical media. 
     The hard disk drive  527 , magnetic disk drive  528 , and optical disk drive  530  can couple with a hard disk drive interface  532 , a magnetic disk drive interface  533 , or an optical disk drive interface  534 , respectively. The drives and their associated computer-readable media provide non-volatile storage of computer-readable instructions, data structures, program modules, and other data for the computer  500 . Any type of computer-readable media which can store data that is accessible by a computer, such as magnetic cassettes, flash memory cards, digital video disks, Bernoulli cartridges, random access memories (RAMs), read only memories (ROMs), redundant arrays of independent disks (e.g., RAID storage devices) and the like, can be used in the operating environment. 
     A plurality of program modules can be stored on the hard disk, magnetic disk  529 , optical disk  531 , ROM  524 , or RAM  525 , including an operating system  535 , one or more application programs  536 , other program modules  537 , and program data  538 . Programming for implementing one or more processes or method described herein can be resident on any one or number of these computer-readable media. 
     A user can enter commands and information into computer  500  through input devices such as a keyboard  540  and pointing device  542 . Other input devices (not shown) can include a microphone, joystick, game pad, satellite dish, scanner, or the like. These other input devices are often connected to the processing unit  521  through a serial port interface  546  that is coupled to the system bus  523 , but can be connected by other interfaces, such as a parallel port, game port, or a universal serial bus (USB). A monitor  547  or other type of display device can be connected to the system bus  523  via an interface, such as a video adapter  548 . The monitor  547  can display a graphical user interface for the user. In addition to the monitor  547 , computers typically include other peripheral output devices (not shown), such as speakers and printers. 
     The computer  500  can operate in a networked environment using logical connections to one or more remote computers or servers, such as remote computer  549 . These logical connections through a communication device coupled to or a part of the computer  500 ; not limited to a particular type of communications device. The remote computer  549  can be another computer, a server, a router, a network PC, a client, a peer device or other common network node, and typically includes many or all of the elements described above relative to the computer  500 . The logical connections depicted in  FIG. 5  can include a local area network (LAN)  551  and/or a wide area network (WAN)  552 . Such networking environments are commonplace in office networks, enterprise-wide computer networks, intranets and the internet, which are all types of networks. 
     When used in a LAN-networking environment, the computer  500  can be connected to the LAN  551  through a network interface or adapter  553 , which is one type of communications device. In one or more embodiments, when used in a WAN-networking environment, the computer  500  can include a modem  554  (another type of communications device) or any other type of communications device (e.g., a wireless transceiver), for establishing communications over the wide-area network  552 , such as the internet. The modem  554 , which can be internal or external, is connected to the system bus  523  via the serial port interface  546 . In a networked environment, program modules depicted relative to the computer  500  can be stored in the remote memory storage device  550  of remote computer  549 . The network connections shown are examples of network connections and other means of, and communications devices for, establishing a communications link between the computers can be used including hybrid fiber-coax connections, T1-T3 lines, DSL&#39;s, OC-3 and/or OC-12, TCP/IP, microwave, wireless application protocol, and any other electronic media through any suitable switches, routers, outlets and power lines. 
     As will be appreciated by one skilled in the art, aspects of the present disclosure can be illustrated and described herein in any of a number of patentable classes or context including any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof. Accordingly, aspects of the present disclosure can be implemented in entirely hardware, entirely software (including firmware, resident software, micro-code, etc.) or in a combination of software and hardware that may all generally be referred to herein as a “circuit,” “module,” “component,” or “system.” Furthermore, aspects of the present disclosure may take the form of a computer program product embodied in one or more computer readable media having computer readable program code embodied thereon. 
     Any combination of one or more computer readable media can be utilized. The computer readable media can be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium can be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an appropriate optical fiber with a repeater, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium can be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. 
     A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium can be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a computer readable signal medium can be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing. 
     Computer program code for carrying out operations for aspects of the present disclosure can be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C#, VB.NET, Python or the like, conventional procedural programming languages, such as the “C” programming language, Visual Basic, Fortran 2003, Perl, COBOL 2002, PHP, ABAP, dynamic programming languages such as Python, Ruby and Groovy, or other programming languages. The program code may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer can be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computer (for example, through the Internet using an Internet Service Provider) or in a cloud computing environment or offered as a service such as a Software as a Service (SaaS). 
     Aspects of the present disclosure are described herein with reference to flowchart illustrations and/or block diagrams of techniques, apparatuses (systems) and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable instruction execution apparatus, create a mechanism for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
     These computer program instructions may also be stored in a computer readable medium that when executed can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions when stored in the computer readable medium produce an article of manufacture including instructions which when executed, cause a computer to implement the function/act specified in the flowchart and/or block diagram block or blocks. The computer program instructions may also be loaded onto a computer, other programmable instruction execution apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatuses or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
     The flowchart(s) and block diagram(s) in the FIGS. illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various aspects of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the FIGS. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions. 
     The terminology used herein is for describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In this document, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. 
     The corresponding structures, materials, acts, and equivalents of any means or step plus function elements in the claims below are intended to include any disclosed structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The aspects of the disclosure herein were chosen and described in order to best explain the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure with various modifications as are suited to the particular use contemplated.