JP5973381B2 - DNS server bypass system, DNS server bypass method, data providing server, and data providing program - Google Patents

Description

The present invention relates to a DNS server bypass system, a DNS server bypass method, a data providing server, and a data providing program that realize a target connection without using a DNS server .

  In communication using a network, DNS resolution is performed by sending a DNS query using a DNS server (DNS cache server) and receiving a DNS response signal. Specifically, when a communication terminal tries to connect to another device via a network, the communication terminal sends a communication query including the domain of the other device to which connection is desired to the DNS server. An IP address corresponding to the domain of the target device can be acquired. Therefore, the communication device can connect to the target device using the acquired IP address.

  However, if an error has occurred in the DNS server that is the inquiry destination, the communication terminal cannot obtain the IP address of the target device. For example, when the DNS server is falsified, DNS resolution using this DNS server cannot be executed. Also, for example, when the DNS server is under repair, DNS resolution cannot be executed.

http://www.ietf.org/rfc/rfc1034.txt.pdf (searched on May 30, 2013)

  Conventionally, when the DNS server as described above cannot be used, DNS resolution cannot be executed, and communication connection with a target device may not be realized.

  In view of the above problems, an object of the present invention is to realize a desired connection without using a DNS server when a connection destination cannot be obtained from the DNS server.

  In order to achieve the above object, the DNS server detour device according to the present invention, when a domain is input after the detour processing is started, from the list data in which the domain related to the past communication history and the IP address are associated with the input domain. An extraction unit that extracts the corresponding IP address is provided.

  According to the present invention, when a connection destination cannot be obtained from a DNS server, a desired connection can be realized without using this DNS server.

FIG. 1 is a block diagram illustrating the configuration of the DNS server bypass device according to the first embodiment. FIG. 2 is a diagram illustrating a network to which the DNS server bypass device of FIG. 1 is connected. FIG. 3 is a flowchart for explaining the flow of processing in the DNS server bypass device of FIG. FIG. 4 is a block diagram illustrating the configuration of the DNS server bypass system according to the second embodiment. FIG. 5 is a diagram for explaining a network to which the DNS server bypass system of FIG. 4 is connected. FIG. 6 is a block diagram illustrating the configuration of the DNS server bypass system according to the third embodiment. FIG. 7 is an example of history data used in the DNS server bypass system of FIG. FIG. 8 is an example of list data generated by the DNS server bypass system of FIG. FIG. 9 is an example of data used in the DNS server bypass system of FIG. It is a figure explaining the investigation range of a DNS server detour system.

  The DNS server bypass system, DNS server bypass device, and DNS server bypass method according to the present invention will be described below with reference to the drawings. The DNS server bypass system and the DNS server bypass device according to the present invention realize a target communication connection without going through the DNS server when the DNS server cannot be used because it is abnormal or under repair. In the following description, the same device or configuration is illustrated using the same reference numeral, and the description thereof is omitted.

<First Embodiment>
As illustrated in FIG. 1, the DNS server bypass device 1A according to the first embodiment includes a transmission / reception unit 11, an error detection unit 12, an extraction unit 13, an update unit 14, an addition unit 15, and a storage device 16. For example, the DNS server bypass device 1A includes an error detection unit 12 and an extraction unit 13 by installing a bypass program in a client terminal or DNS server (DNS cache server) having a transmission / reception unit 11 and a storage device 16 that perform DNS resolution. The updating unit 14 and the adding unit 15 are mounted, and a predetermined communication connection can be realized without performing DNS resolution using the DNS server 2 in a predetermined case.

  For example, as illustrated in FIG. 2A, the client terminal 1 transmits a DNS query to the connected DNS server 2 when trying to acquire the IP address of the server 3 in the domain “b”. When the DNS server bypass device 1A can receive a response including the IP address “5” in response to the transmitted DNS query, it can connect to the server 3 of the target domain.

  On the other hand, if an abnormality such as falsification has occurred in the connected DNS server 2, the client terminal 1 cannot obtain a correct IP address and cannot connect to the target server 3. Further, when the DNS server 2 is under repair and cannot be accessed, the client terminal 1 cannot obtain an IP address connected to the target server 3.

  On the other hand, as shown in FIG. 2B, the DNS server bypass device 1A according to the first embodiment has itself even when the connected DNS server 2 cannot be used. The target IP address “5” is specified from the data, and the target server 3 is accessed.

  The example shown in FIG. 2 has been described with an example in which the DNS server bypass device 1A is a client terminal, but the same applies to the case where the DNS server bypass device 1A is a DNS server connected to the client terminal or another DNS server. is there.

  When performing DNS resolution, the transmission / reception unit 11 transmits a DNS query including a domain to the DNS server 2 and receives a DNS response signal including an IP address corresponding to the domain. Here, when the same DNS resolution is performed within the past predetermined time (when there is valid cache data), the DNS server bypass device 1A may perform DNS resolution by referring to the history.

  The timing at which the transmission / reception unit 11 executes DNS resolution is the timing at which the domain is input. For example, when the DNS server bypass device 1A is a client terminal, the domain of the server that is the access destination is input or selected by the user. Is the case. Further, when the DNS server bypass device 1A is a DNS server, it is a timing when a DNS query including a domain transmitted from a connected client terminal or another DNS server is input.

  The history data D1 is data relating to a history of DNS resolution performed by the DNS server bypass device 1A. Specifically, the history data D1 includes a combination of “domain” and “IP address” obtained by DNS resolution.

  When the transmission / reception unit 11 resolves the IP address by DNS resolution, the addition unit 15 adds the history including the domain and the IP address to the history data D1.

  The list data D2 is data generated using the history data D1, and is data obtained by extracting the history data D1 that has a high frequency of DNS resolution. That is, the list data D2 also includes a combination of domain and IP address. For example, a client terminal that is the DNS server bypass device 1A generally has a certain tendency in access to the server. Specifically, users often access regularly to store data on a certain server, or regularly access a fixed Web site and browse Web pages. Therefore, in the list data, such a DNS server bypass device 1A is data having data relating to a server that is frequently used.

  The update unit 14 reads the history data D1 from the storage device at a predetermined timing, generates list data D2 using data extracted from the history data D1 under a predetermined condition, and stores the list data stored in the storage device 16 D2 is updated to the newly generated list data D2. For example, a predetermined number of histories having a high access frequency are extracted from the communication histories included in the history data D1 for a certain period (for example, one month), and the history data D1 are rearranged in descending order of the access frequencies. Here, the number of histories included in the list data D2 generated by the update unit 14 and the data size of the list data D2 can be determined by the processing capability of the DNS server bypass device 1A and the storage capacity of the storage device 16. Further, the timing at which the update unit 14 generates the list data may be a periodic timing or a timing at which the error detection unit 12 detects an error. This timing can be set according to, for example, the processing capability of the DNS server bypass device 1A and the data amount.

  The error detection unit 12 detects an error of the connected DNS server 2. Specifically, the error is when the DNS server 2 has been tampered with or when the DNS server 2 cannot be connected, such as at the time of repair or failure. The error detection unit 12 can detect an error using, for example, SNMP abnormality detection. Note that when the secondary of the connected DNS server 2 is usable, the DNS server bypass device 1 uses the secondary server, so the error detection unit 12 does not detect it as an error.

  The extraction unit 13 extracts the IP address corresponding to the input domain from the list data D2 when the transmission / reception unit 11 inputs a domain for DNS resolution after the DNS server bypass device 1A starts the DNS server 2 bypass processing. . Here, the list data D2 used for extraction by the extraction unit 13 is data generated based on the frequency of use, unlike normal cache data. Therefore, the extraction unit 13 easily extracts a target IP address. be able to.

  Here, the timing at which the DNS server bypass device 1A starts the bypass processing of the DNS server 2 is, for example, the timing at which the error detection unit 12 detects an error in the DNS server 2. Alternatively, it is the timing when the DNS server bypass device 1A inputs a start signal for starting the bypass processing. This start signal is input from, for example, a server to which the DNS server bypass device 1A is connected.

  Further, the extraction unit 13 outputs the IP address extracted from the list data D2 to the transmission / reception unit 11. Note that when the error detection unit 12 detects the resolution of the error, the DNS resolution using the list data D2 is unnecessary, and therefore the extraction of the IP address by the extraction unit 13 is not executed.

  The transmission / reception unit 11 can generate a DNS response signal using the IP address input from the extraction unit 13 as a search result.

  Here, when the IP address is an IP address of “specific domain” by the extraction unit 13, the transmission / reception unit 11 may generate a response signal including a message warning that the IP address is a specific domain together with the IP address. Specific domains include, for example, blacklisted domains, domains related to advertisement data, overseas server domains, data domains that are not preferred by users, and domains that may damage devices that receive data from these domains. It is. For example, the history data D1 and the list data D2 have a flag relating to such a specific domain, and when this flag is set to ON, a response signal including a message can be generated.

  For example, the DNS server bypass device 1A can acquire data on a specific domain and its IP address from an external server or the like. Also, the DNS server bypass device 1 sets the domain and IP address of the list data D2 at the timing of generating the list data D2 by the updating unit 14 or at the timing of predetermined batch processing based on the acquired data on the specific domain. Flags for specific domains can be set.

  When the extraction unit 13 cannot extract the IP address, that is, when the list data D2 does not include the IP address, the transmission / reception unit 11 generates a response signal including a message whose IP address has not been searched. . In addition, when an IP address can be obtained by inquiring through another route, a response signal including the IP address obtained by another route may be obtained.

  When the DNS server bypass device 1A is a client terminal, the DNS server bypass device 1A executes access to the IP address included in the signal generated by the transmission / reception unit 11. When the DNS server bypass device 1A is a DNS server, the transmission / reception unit 11 transmits the generated signal to the client terminal that transmitted the DNS query or another DNS server.

  An example of processing executed by the DNS server bypass device 1A will be described using the flowchart shown in FIG. First, after the error detection unit 12 of the DNS server bypass device 1A detects an error (S1), when the transmission / reception unit 11 inputs a domain (S2), the extraction unit 13 receives an IP address corresponding to the domain input from the list data D2 Is extracted (S3).

  The IP address corresponding to the domain input by the extraction unit 13 is extracted from the list data D2 (YES in S4). When this domain is not a specific domain (NO in S5), the transmission / reception unit 11 is extracted by the extraction unit 13 A DNS response signal including the IP address is generated and output (S6).

  On the other hand, when this domain is a specific domain (YES in S5), the transmission / reception unit 11 generates and outputs a response signal including a warning message that is the specific domain (S6). Here, the transmission / reception unit 11 outputs the IP address of the site that displays the warning message, and after confirming this message, the connection is executed only when a request for connection to a specific domain is received. You may do it.

  For example, when the IP address cannot be extracted by the extraction unit 13 (NO in S4), the transmission / reception unit 11 generates and outputs a response signal including a message indicating that the IP address cannot be extracted (S7). Also in this case, the transmission / reception unit 11 may output the IP address of the site that displays a message that the IP address cannot be extracted.

  As described above, in the DNS server bypass device 1A according to the first embodiment, even when it is not possible to connect to the connected DNS server 2, the connection destination is determined using the history related to the communication history of the own device. You can search. Therefore, it is possible to prevent a situation in which communication connection caused by an error of the DNS server 2 cannot be realized.

Second Embodiment
As shown in FIG. 4, a DNS server bypass system 100B according to the second embodiment includes a DNS server bypass device 1B, a data providing server 4B, and a DNS server 2.

  For example, as shown in FIG. 4, the DNS server bypass device 1B installs a bypass program in a client terminal or DNS server (DNS cache server) having a transmission / reception unit 11 that performs DNS resolution. The extraction unit 13 and the addition unit 15 are mounted, and a target communication connection can be realized without performing DNS resolution using the DNS server 2 in a predetermined case.

  Here, the DNS server bypass device 1A of the first embodiment described above with reference to FIG. 1 has the update unit 14, whereas the DNS server bypass device 1B of the second embodiment has the update unit 14. Not different in that. In the DNS server bypass device 1A, the update unit 14 generates the list data D2 from the history data D1, but the DNS server bypass device 1B shown in FIG. 4 does not generate the list data D2 in its own device. Data provided from the providing server 4B is used. In FIG. 4, only one DNS server bypass device 1B is connected to the data providing server 4B, but a plurality of DNS server bypass devices may be connected.

  The data providing server 4B includes a collecting unit 41, an analyzing unit 42, a providing unit 43, and a storage device 44. This data providing server 4B obtains data related to the communication history using the DNS resolution of the DNS server bypass device 1B from the DNS server bypass device 1B, analyzes this, generates list data, and provides it to the DNS server bypass device 1B To do. Therefore, the DNS server bypass device 1B does not need to generate list data, and may use list data provided from the data providing server 4B.

  The collection unit 41 collects data related to a communication history including a domain and an IP address from the DNS server bypass device 1B, and stores the collected data as history data D3 in the storage device 44. For example, the collection unit 41 periodically collects data, adds newly collected data, and updates the history data D3.

  The analysis unit 42 reads the history data D3 stored in the storage device 44, analyzes the history data D3, generates list data D4, and stores the list data D4 in the storage device 44. For example, like the updating unit 14 described with reference to FIG. 1, the analysis unit 42 extracts data having a high access frequency in a certain period from the history data D3, and generates the list data D4 in the order of the high access frequency. . For example, the analysis unit 42 periodically generates list data D4. Here, the number of domains included in the list data D4 and the data size of the list data D4 can be determined according to the processing capability of the data providing server 4B and the storage capacity of the storage device 16 of the DNS server bypass device 1B.

  The providing unit 43 reads the list data D4 stored in the storage device 44 and provides it to the DNS server bypass device 1B. For example, the providing unit 43 provides the list data D4 to the DNS server bypass device 1B at the timing when the analysis unit 42 generates new list data D4 or when the request is received from the DNS server bypass device 1B.

  For example, as shown in FIG. 5A, normally, when the client terminal 1 tries to obtain the IP address of the server 3 in the domain “b”, the client terminal 1 performs DNS resolution using the connected DNS server 2. ing. On the other hand, when an error such as falsification occurs in the connected DNS server 2, the client terminal 1 cannot acquire the IP address of the target domain from the DNS server 2.

  Therefore, in the DNS server bypass system 100B according to the second embodiment, when an error occurs in the connected DNS server 2, the DNS server bypass device 1B uses the list data D4 provided from the data providing server 4C to You can get the IP address of the domain. As a result, the DNS server bypass device 1B can acquire data without using the DNS server 2.

  As described above, in the DNS server bypass device 1B of the DNS server bypass system 100B according to the second embodiment, even if it is not possible to connect to the connected DNS server 2, past communication is performed by the data providing server 4B. The connection destination can be searched using data generated using the history. Therefore, it is possible to prevent a situation in which connection caused by an error of the DNS server 2 cannot be realized.

  Further, in the DNS server bypass device 100B, the data providing server 4B can generate list data and provide it to the DNS server bypass device 1B. Therefore, even if the DNS server bypass device 1B does not have sufficient processing capability. When the DNS server 2 has an error, DNS resolution using the past history can be executed.

<Third Embodiment>
As shown in FIG. 6, the DNS server bypass system 100C according to the third embodiment includes a DNS server bypass device 1C, a data providing server 4C, and a DNS server 2. The data providing server 4C is connected to a plurality of client terminals 5a to 5c via the network N.

  When the data providing server 4C shown in FIG. 6 and the data providing server 4B described above with reference to FIG. 4 are compared, the data providing server 4C is connected to a plurality of client terminals 5a to 5c via the network N. It is different. FIG. 6 shows an example in which the client terminals 5a to 5c are connected to the data providing server 4C. However, the apparatus connected to the data providing server 4C is an apparatus that performs DNS resolution in addition to the client terminal. As long as it is a (communication terminal), it may be a DNS server or a router device in addition to the client terminal. Moreover, the number is not limited.

  The collection unit 41 of the data providing server 4C collects history data from the DNS server bypass device 1C and also collects history data from the plurality of client terminals 5a to 5c. Therefore, the history data D3 stored in the storage device 44 of the data providing server 4C includes data collected from a plurality of devices as shown in FIG. For example, in the example of the history data shown in FIG. 7, the communication history of the user A using the DNS server bypass device 1C, the communication history of the user B using the client terminal 5a, the communication history of the user C using the client terminal 5b, and The communication history of the user D who uses the client terminal 5c is included.

  The analysis unit 42 reads the history data D3 from the storage device 44, analyzes the read history data D3, and generates list data D4. At this time, as shown in FIG. 8, the analysis unit 42 may generate list data D4 having a high access frequency for each user. For example, FIG. 8A shows data generated from user A's history, and FIG. 8B shows data generated from user B's history.

  In addition, as shown in FIG. 9A, the storage device 44 stores data relating to user attributes including “user ID”, “age”, “blood type”, “birthplace”, etc. As shown in FIG. 9B, the unit 42 extracts users (for example, users in their 30s) who meet certain conditions, and generates list data from the extracted user history. Also good. At this time, when there are a plurality of IP addresses for the same domain, the analysis unit 42 may include the plurality of IP addresses together with the order of candidates. For example, in the example illustrated in FIG. 9C, an IP address in which the “candidate 1” flag (IPb) is set is an IP having a more usage history than an IP address in which the “candidate 2” flag (IPd) is set. Address. Further, as shown in FIG. 9C, the analysis unit 42 sets flags (black list flag (b), advertisement flag (ad), etc.) for the specific domain and turns on these flags. Thus, use in the DNS server bypass device 1C may be restricted.

  As described above, in the DNS server bypass device 1C of the DNS server bypass system 100C according to the third embodiment, even if it is not possible to connect to the connected DNS server 2, the past communication is performed by the data providing server 4C. The connection destination can be searched using data generated using the history. Therefore, it is possible to prevent a situation in which connection caused by an error of the DNS server 2 cannot be realized.

  Further, in the DNS server bypass device 100C, the data providing server 4C can generate list data and provide it to the DNS server bypass device 1C. Therefore, even if the DNS server bypass device 1C does not have sufficient processing capability. When the DNS server 2 has an error, DNS resolution using the past history can be executed.

  Further, in the DNS server bypass device 1C, the DNS server bypass device 1C provides not only the history of the device itself but also the list data generated by the data providing server 4C from the history of a plurality of users to the DNS server bypass device 1C. The own device can also obtain IP addresses that have no DNS resolution history.

  In the above-described example, as shown in FIG. 10, an example is different from a physical network connection route, a router device virtual connection route, and a DNS server virtual connection route. As shown in FIG. 10, it is assumed that GWs (gateways) 1a to 1h exist on the network. Further, it is assumed that these GWs can be executed as the DNS server bypass device of the present invention.

  At this time, users who own GWs 1a, 1b, and 1e have the same provider contract and use the same DNS server 2. When this provider repairs the DNS server 2, the GWs 1 a, 1 b, 1 c, and 1 d connected to the same router 6 do not execute processing as the DNS server bypass device of the present invention, but the same DNS server 2. The connected GWs 1a, 1b, and 1e start the detour processing of the DNS server 2 as the DNS server detour device described above. The start signal for starting the detour processing of the DNS server 2 for the DNS server detour devices GW1a, 1b, and 1e is sent to another server that manages the GW (or OSGi center server if OSGi operates on the GW) or This is performed from the DNS server 2 or another server that manages the DNS server 2 via a router connected to the GW. As described above, when it is known in advance that the DNS server 2 cannot be used, such as when the DNS server 2 is repaired, the DNS server bypass device can perform processing in preparation for the DNS server 2 bypass. It is inefficient for the router to start as a DNS server bypass device.

  As mentioned above, although this invention was demonstrated in detail using embodiment, this invention is not limited to embodiment described in this specification. The scope of the present invention is determined by the description of the claims and the scope equivalent to the description of the claims.

100B, 100C ... DNS server bypass system 1A to 1C ... DNS server bypass device 11 ... Transmission / reception unit 12 ... Error detection unit 13 ... Extraction unit 14 ... Update unit 15 ... Addition unit 16 ... Storage device
D1 ... History data
D2 ... List data 2 ... DNS server 4B, 4C ... Data providing server 41 ... Collecting unit 42 ... Analyzing unit 43 ... Providing unit 44 ... Storage device
D3 ... History data
D4 ... List data 5a-5c ... Client terminal

Claims (4)

A DNS server bypass system comprising a DNS server bypass device connected to a DNS server and a data providing server connected to a plurality of communication terminals,
The data providing server includes:
A collection unit that collects history data in which domains and IP addresses related to communication histories of a plurality of communication terminals are associated with attributes of a user who operates the communication terminal that has performed the communication,
Analyzing the history data collected by the collection unit, an analysis unit for generating list data by domain and IP address corresponding to the user attribute corresponding to the DNS server bypass device;
A providing unit for providing the list data generated by the analysis unit to the DNS server bypass device;
The DNS server bypass device
When a domain is input after starting the detour processing, an extraction unit that extracts an IP address corresponding to the input domain from the list data received from the data providing server,
DNS server bypass system characterized by that. A DNS server bypass method realized by a DNS server bypass system comprising a DNS server bypass device connected to a DNS server and a data providing server connected to a plurality of communication terminals ,
In the data providing server, collecting history data in which domains and IP addresses related to communication histories of the plurality of communication terminals are associated with attributes of a user who operates the communication terminal that has performed the communication ;
In the data providing server, analyzing the collected history data, and generating list data by a domain and an IP address corresponding to a user attribute corresponding to the DNS server bypass device ;
In the data providing server, providing the generated list data to the DNS server bypass device;
In the DNS server detour device, starting detour processing;
In the DNS server bypass device, after detecting an error, inputting a domain for DNS resolution, extracting from the list data received from the data providing server an IP address corresponding to the input domain;
A DNS server bypass method characterized by comprising:   A DNS server bypass device connected to a DNS server and a data providing server connected to a plurality of communication terminals,
  A collection unit that collects history data in which domains and IP addresses related to communication histories of a plurality of communication terminals are associated with attributes of a user who operates the communication terminal that has performed the communication,
  Analyzing the history data collected by the collection unit, an analysis unit for generating list data by domain and IP address corresponding to the user attribute corresponding to the DNS server bypass device;
  Providing unit that provides the DNS server detour device with the list data generated by the analyzing unit
  And a data providing server.   A data providing program used for a DNS server bypass device connected to a DNS server and a data providing server connected to a plurality of communication terminals,
  A computer that is the data providing server;
  A collection unit that collects history data in which domains and IP addresses related to communication histories of a plurality of communication terminals are associated with attributes of a user who operates the communication terminal that has performed the communication,
  Analyzing the history data collected by the collection unit, an analysis unit for generating list data by domain and IP address corresponding to the user attribute corresponding to the DNS server bypass device;
  Providing unit that provides the DNS server detour device with the list data generated by the analyzing unit
  A data providing program characterized by functioning as

Images